This hack was inevitable. Mt Gox deals with millions of dollars per month and was ripe for the picking. I bet there's a million dollars stored in accounts on the site right now, and millions more in BTC. The withdrawl limit saved Mt Gox, this time, but next time they won't be so lucky.
I am unlikely to use Mt Gox ever again after this. It's the equivalent of the NYSE or FTSE being hacked and all shares sold. If we're to treat BTC seriously we need serious security and service. This hacking shows just how flaky bitcoin can be and despite the claims of P2P, security, etc, it's almost totally reliant on a few nodes for trading and bitcoin creation.
We know very little as of yet. I think you may be overreacting. At worst someone stole tons of coins, at best they got 1000 USD from a site that makes tons and tons each day. One is a huge deal, the other is a minor annoyance.
There is no overeacting here. Mt Gox had no automatic safeguards and logic checks to ensure the market could not be compromised. Gox is no longer a Magic The Gathering trading site. They are dealing with serious amounts of money with no auditing or regulation. How was taking a BTC's value down 99.95% within minutes not stopped by the exchange? I know the rabid libetarians will say it was the will of the market, and if it needs to fall to zero and back again then so be it. Witness the sheer unbridled greed of some posters on this forum who managed to snag BTCs at 99% off, and now whining that the trades will be rolled back.
We truly don't know the extent of this attack yet. If it was done properly, the script should have transferred out as many BTCs as possible before the market was shut. Those cannot be retrieved.
Pardon me for being a newb, but can't we just look at the block chain to determine an upper bound on how much was withdrawn from MtGox today?