Decentralized network

Ripple is a distributed network – meaning it does not rely upon one company to maintain and protect the database. This provides two main benefits. First, transaction confirmations happen across the entire network at the same time so no more waiting for block confirmations. Second, because it is a peer-to-peer system, there is no central target or point of failure in the system. This means more stability for the entire BTC community.

To take out the bitcoin network, you only have to attack the relatively few nodes that allow incoming connections, most of which are running on commodity hardware at users' homes. Taking out one of the largest sites on the internet is a completely different story.

Also, the bitcoin network provides no guarantees about the accuracy or security of the data it carries - so you gain nothing from getting your data from it compared to from some other source. That is in fact, pretty much the whole innovation of Bitcoin - that each node can arrive at the same globally consistent view, with zero trust of anyone else on the network, instead determining for itself whether it thinks the data is legitimate.

ugh... thats what the wiki sounded like :/

So all these free sites that send tiny amounts of BTC Ex .00,002,080 are like what, largely unspendable?

Ok I see.  And I agree that Satoshi Dice is an idiotic waste of block space, but if Bitcoin can't handle Satoshi Dice, then we can wave goodbye to the idea of Bitcoin ever competing with Paypal or being widely accepted in stores, restaurants, and other places which would be doing small transactions.  It seems to me that with the way things are now, we will be limited to using Bitcoin as a store of value and a means of transferring money. 

When people talk about the tx fee rising we aren't talking about the min mandatory fee (which is designed to prevent spam attacks on the network) but rather competition will require users to pay more to get included in a block.

Worst case scenario: we end up with fractional reserve banking with "dollar-coins" where the mint holds 1:10 of the circulation in real dollar deposits since the mint is sure everyone wont withdraw the "dollar-coin" for real dollars at the same time.

You can't build a a block without knowing the previous block.  You don't know that until the new block is finished.

Hmm.  Header can be downloaded in parallel / separately to the block body, and hashing can start after receiving just the header.  Milliseconds amount of time.  Perhaps a "quick" list of outputs spent by the block would be useful for building non-trivial blocks that don't include double-spends, but that would be ~5% of the block size?  Plenty of room for "optimization" here were it ever an issue.

Fake headers / tx lists that don't match the actual body?  That's a black mark for the dude who gave it to you as untrustworthy.  Too many black marks and you ignore future "headers" from him as a proven time-waster.

Build up trust with your peers, just like real life.

1. Your concerns about how to port in real-world cash are unfounded. There already exists an industry of businesses that will take cash in many forms and give virtual credits, including bitcoins, for them... BitInstant, Dwolla, OKPay, coinbase, ArumXchange, and many others can upload cash into this exchange in one or more forms. Let them deal with this headache; there are many of them so there is no central point of failure there.

Arguably OT, but still important to the thrust of the OP and much of the debate where network security = decentralization.
Astounding developments like this will drive forward Bitcoin's success.

Larger blocks will potentially cause bandwidth issues when you try to propagate them though, since you have to send all the transactions.