BTW I don't think Bitcoin is undefeatable, you can always destroy it by 51% attack. And that's why I think it is amazing: you can choose.
There are solutions for the 51% attack situation. When the fix needs to be implimented it will be. Gavin and others have had the solution ready for awhile now. The whole 51% thing just makes good press, it's all about selling fear, thats why you never hear that a 51% attack would be noticed immediately and the fix would shut the attack down almost immediately making all the attackers blocks invalid. To the normal citizen Bitcoin user it would be a small "hiccup" and banks have big "hiccups" all the time and no one really complains. Banks even close on the weekends and are getting hacked/fraud/ID thefts daily.
I don't know where you get your delusions, laser brain.
Gavin: "The code already has a notion of (bitcoin priority) that it uses to prevent transaction spam (sending gazillions of tiny transactions to yourself, just to make everybody else do the work of validating and storing them); extending that to influence the chain-fork-selection code wouldn't be hard....something like....ignore a longer chain orphaning the current best chain if the sum(priorities of transactions included in new chain) is much less than sum(priorities of transactions in the part of the current best chain that would be orphaned) would mean a 51% attacker would have to have both lots of hashing power AND lots of old, high-priority bitcoins to keep up a transaction-denial-of-service attack. And theyd pretty quickly run out of old, high-priority bitcoins and would be forced to either include other peoples transactions or have their chain rejected".
In Andresens post, he notes that such a solution would be Not To Be Used Except In Case of Emergency.