Well, private keys are data that certainly any future Bitcoin client should be able to import (being backwards-compatible is pretty much a given).  Now if the data is in QR code form and a few years from now QR codes are obsolete (let's say some other data transfer becomes used and QR codes fall by the wayside) then there should also be the private key printed so that it could be manually entered as well, I suppose.

The term "noob-friendly" means someone is handling the gory details for the noob.   That's what a hosted (shared) EWallet does.  Coinbase, for instance, might be considered as being noob-friendly.  The problem is they store the user's coins, and thus the user doesn't get the private keys, only the ability to make deposits to those addresses and the ability to submit requests for withdrawals.

But you don't get much simpler than something like Coinbase for noobs.  There's no mobile app from them though.  

If a mobile app is desired, then your options go to Blockchain for Android (or iOS) or Bitcoin Wallet for Android.    But depending on your definition of noob, those methods require some tech competency so as to not lose your funds (e.g., with Blockchain, to also log in via web, then link the mobile, assign an alias to the account, set up an e-mail and have backups delivered via e-mail, etc.)

So the answer really is ...  sorry, there are no local wallet options that are noob-friendly.   Well, there is.  It is called a Casascius physical bitcoin.  Once it arrives by mail, throw it in the safe.  You now have yourself a noob-friendly bitcoin wallet that is secure and a year or so from now when good noob-friendly local wallet options are available that coin can be traded with someone who will load up the noob-friendly wallet with some value in exchange for the Casascius coin.

The most efficient GPU (in terms of Mhash/s/$) is the ATI HD 5830 which scores 3.28  (whereas a 6990 scores a 1.23).  

The most efficient FPGA is the BFL single which scores a Mhash/s/$ of 1.64 (but provides better profit than a 5830 after considering the cost of electricity).

The most efficient ASIC is the Avalon ASIC which scores a Mhash/s/$ of 52.34.   Followed behind that is the BFL Mini Rig SC at 50.16.   The BFL rig might yield better than the Avalon ASIC as it is more efficient on a Mhash/s/J (power consumption), but electricity consumption is nowhere near the most important factor these days (... delivery dates are).

These numbers are from the Mining Hardware comparison article:
 - http://en.bitcoin.it/wiki/Mining_hardware_comparison#FPGA

[Edit, Oops. fixed, added the K, thanks D&T.]

So a price of hardware per Thash/s would be the inverse I suppose,
 GPU: $305K per Thash/s
 FPGA: $609K per Thash/s
 ASIC: $19K per Thash/s

Why would my spending using bitcoins be impacted by your decision to save your bitcoins?

Sure, fewer of your coins for sale on the market means the exchange rate is today higher but if I want to buy something, say ... a new laptop on BitcoinStore.com, why would I be more or less likely to do that just because you happened to not spend your coins?

Additionally, while not entirely a hassle for me to cash out my coins, it is an extra step.  So if I already have bitcoins or I receive bitcoins as income (e.g., dividends from some stocks I might own, or maybe a really good string of luck on http://bitZino.com) then I'm more likely to patronize a bitcoin merchant than to cash those funds out and use the cash proceeds to make my purchase.   If I want to replenish my stash of bitcoins using dollars, I can always do a trade using Coinlab or something like that so that I can spend my bitcoins yet at the same time maintain a level of savings of bitcoins that doesn't change much over time.

The only problem with "hoarding" is that if the exchange rate were to head the other direction, those whose only interest in Bitcoin is for speculation then start to bail out and dump their coins.  This introduces exchange rate volatility which isn't a desirable property of a currency.  

The thing is though, this increasing exchange rate is helping significantly to fund quite a few Bitcoin-related startups.   BitPay just raised another round of funding, for instance, in which investors include those who have benefited from a rising exchange rate (fueled by your hoarding).  As a result, the rising exchange rate is helping to build a stronger bitcoin economy.

Another way the rising exchange rate is helping is by creating liquidity as well.  A year ago, at a $120 million total dollar valuation (of all bitcoins combined) a company wanting to buy and send $25K USD worth of bitcoins to a supplier would have had an impact on the exchange rate -- order book depth was pretty thin and a $25K buy was a big deal.  Even worse, the supplier that received the coins would then go to cash out and that same $25K worth of coin would clobber the exchange rate in the other direction.    So a larger valuation allows larger transactions to occur efficiently (less of a whipsaw effect from larger transaction sizes).

So your hoarding helps bitcoin to gain traction.

Thank you for hoarding.

Pro tip: If you have at least twice as many BTCs in your BitStamp wallet as you need to withdraw, put in a withdraw request now to a local wallet (e.g., Bitcoin-Qt), and within minutes you'll know if it is instant or delayed.  Maybe start out with like 15 BTC and then work your way up until you have all that you need withdrawn.  Then once they are in your own local wallet you have the control over sending them at your convenience.

In a worst-case scenario where your withdrawal gets queued, then I believe BITSTAMP has redeemable codes (coupons they call them), which you could probably do a trade.  You send someone a BITSTAMP redeemable code, and they send to you bitcoins.  The person redeeming your coupon gets the BTCs credited right away and you get the BTCs from the person you did the deal with.

Of course, you would only want to do this with a trusted counterparty, presuming you are asked to send first.  Since there are no fees for the redemable codes (coupons), using an escrow is both easy and affordable for something like this.

Escrow list
 - http://bitcointalk.org/index.php?topic=108716.0

Yup.  two caveats.  The first being that you want to keep backups of your wallet.dat.  With two clients running (each with its own wallet) make sure to have some way of identifying which wallet is which (e.g. if backup up to a flash drive, make a unique folder name for both computer A and computer B).

The second ... if your wallet had Bitcoin addresses that were used (i.e., received a payment) prior to performing the passphrase encryption step then you may want to spend those funds (to a new address, even if in the same wallet) so that you have no funds remaining in any Bitcoin addresses that were in use prior to when you did the encrypt step.

For instance, if you have an old backup of the wallet.dat and then you protect your wallet with Bitcoin-Qt's passphrase encryption, the keys in that old backup are still unencrypted and could be used to create a spend transaction.   But as soon as those funds are spent you no longer need to worry about that old wallet.dat floating around somewhere.

[Edit: Incidentally, I see a Question on StackExchange for this topic as well:

How can I tell if my Bitcoin-Qt wallet is protected with encryption?
 - http://bitcoin.stackexchange.com/questions/8125 ]

Does the username need to be the same as my forum name?  Maybe I'm a shitty poker player and don't want to use my real name as I'ld be embarrassed from how I play. [True story].

Also, what if there is a username/forumname collision and someone else had already registered using my forum username?  [Hypothetically speaking here ...]

You'll need to delete and re-list.

If you aren't going to be online then you probably want to put your e-mail in the description for the order as the method to use to contact you.

e..g.,

 ;;buy 1.0 BTC at "{mtgoxbid}" USD "PayPal or Dwolla payment.  Contact me at: blah@blah.com"

Anyone who wants to lock in the ability to sell a BTC at $39 today (but simply won't get the cash until September 15th).  That's who.

OK, usually when someone describes integrating bitcoin in a website they are referring to how you can accept bitcoins for payment.  That's not too difficult nowadays thanks to many e-commerce shopping cart module interfaces that have Bitcoin support -- especially if using a payment processor such as BitPay, WalletBit, etc.  

But what you are talking about is providing wallet services.  In other words, you are planning on having your site operate a hosted (shared) EWallet in which your customer's funds are held.  That is quite a bit different.  That's like building a bank, to some degree.  Such a project should begin with security considerations and functionality offered would only extend from there.  Here's good reading on the subject:

So you think you're going to start a Bitcoin business, right?
 - http://bitcointalk.org/index.php?topic=124441.0

Bitcoin is a protocol.  It is an open -- it can be used by anyone from anywhere.

Do they use http:// in Brazil?   Do they use SMTP in China?   Or how about XMCP/Jabber in Tanzania?

Yes on all counts because those are all open protocols.

Now because of differing languages, governance, cultures, geography, and rates technological adoption there will be some areas in which Bitcoin gains traction and others in which it lags far behind. 

But just like how there is now an intro site for those who read Swahili (the language local to many in Africa, including Kenya), Bitcoin's reach is expanding further every day.
 - http://www.bitcoins.co.ke

Heh, happens to many of us at some point ...

In your Blockchain.info/wallet you can click Import/Export then when it presents you the warning, click "I Understand".
Then on the left click Export Unencrypted.  You can then choose Bitcoin-Qt format.

Now just to recap, from what I gathered from your post:

You created a Blockchain.info/wallet and never imported any keys.  You have received coins to an address(es) in the wallet.  But when you attempt to spend those funds received you get an error saying
  "address doesnt match the private key"

If that is accurate then you might want to open a support ticket:
 - https://blockchain.zendesk.com

Ah, .. you hadn't mentioned that.


Doesn't really work that much better for delivering coins either (e.g., important notices getting flagged as spam by gmail, for instance)

If the problem was something like a typo in the e-mail address then you might be able to get that resolved.  For example, if you entered tormail.net instead of tormail.org, then that would be something Coinapult support would be able to determine as being an error and thus redeliver to the correct domain.  If instead it was a typo on the email user part, e.g., mindset not m1ndset, then that will be something that will take time as they may need take steps to verify that your inquiry isn't an attempt to swipe coins when the intended recipient really was the "mindset" user.   Or there was a typo and it bounced but since you didn't put in a return address the bounce doesn't go anywhere -- then that's easy to determine the claim of non-delivery would be legit.

But nobody can really help you much other than someone from Coinapult.

Once your nick is registered, you can enable 'enforce'. This will force any user claiming the nick to identify with the password within 30 seconds. This protects you from imposters taking your nick while you're offline. Since you configured your client to automatically identify, nothing changes for you (except being protected).



If you can authenticate then you are done.  It is yours.   Just make sure you have a backup of your GPG private key (and kept secure) and maybe revocation key as well.

Here's some more info on that topic:
 - http://en.bitcoin.it/wiki/Tax_compliance

The cart software that supports BitPay will be different from one that supports a different payment processor.

BitPay's is:
 - https://bitpay.com/bitcoin-shopping-cart-plugins

WalletBit's is:
 - https://walletbit.com/shop

Egg meet anonymous donor:

Missed out on Ripple!
 - http://bitcointalk.org/index.php?topic=145801.0

Well, it doesn't like your current Wallet.dat.

There were instances where an older release of the client was ignorant of the wallet.dat becoming corrupted, and only did the newer releases detect that.  So if that was the case, one could downgrade back to the old version, export the private keys, then create a new wallet in the latest release and import the keys.

Of course, if you have a recent backup try using that first to see if the problem also exists with that.

Some people have had luck accessing the wallet.dat using pywallet even when the Bitcoin.org client couldn't.

Worst case scenario try launching the Bitcoin-Qt client with  -salvagewallet, which will cause the current wallet.dat to be renamed, and then it will create a new one with what it was able to pull from the damaged wallet.dat.   There's no guarantee it will pull all the keys/addresses but if nothing else works this might resolve your problem.