Feature request: ability to set stop loss and take profit levels for open orders. (Or am I just missing it in the UI?)

Can you list the transaction IDs that are not getting confirmed?

My guess is that they were small transactions, below the "dust" threshold.

This 5 post thing is quite annoying.

While they may be registered in the UK, it appears as if they are actually doing business in Slovenia. No big ideal, but it's good to know.

Check out these two pages:

https://en.bitcoin.it/wiki/Selling_bitcoins
https://en.bitcoin.it/wiki/Category:Exchanges

Basically, the idea is that you sell your bitcoins on an exchange, and then transfer the money to your bank from there. There's quite a multitude of ways to do this.

You do not have to back it up every time you make a new transaction, because all of the transactions are stored in the blockchain. If you add a new address to your wallet then you should back it up, because the private key for that address won't be in the earlier backups that you made.

So: if you add a new bitcoin address to your wallet, you need to back it up. New transaction, no.

Play Satoshi Dice

Download a miner and start mining, and it will become more clear how it works. I don't think SLI makes any difference - just as long as the miner can use all of the cards.

If you're using SLI you must have an Nvidia card. Nvidia cards don't typically mine as quickly as ATI cards, you should check this out if you haven't already: https://en.bitcoin.it/wiki/Mining_hardware_comparison#Nvidia