No, because attacks don't directly devalue the currency. People panicking over attacks does, but the eb and flow of the process is months> in magnitude which is certainly enough stability for the amount of people participating in the system currently. MG is completely rebuilding their system and that will be in place by the end of the year so wait until then if you're really concerned about it. If bitcoins fails it will be from the number of people trading greatly exceeding the amount of computing power people donate to validate the transactions (proponents argue the BTC incentive to donate cpu should be enough but you never know..). But this death will be a slow and clunky one, arising from a system that may be too overstable by nature.
It may not end up being bitcoins, but a currency of the same concept is clearly the direction money will head. People can jump on the front end now and share some spoils or be the luddite that missed out on the .com boom because they were too scared of the bubble.