Here's another story about a flaw which allowed someone to withdraw far more than their account balance (at another exchange, not related to this BTC *cough* "problem" *cough*)
http://www.reddit.com/r/Bitcoin/comm..._exchange_and/
Mintpal was also fleeced of 40 BTC somehow...
Makes you wonder how many exchanges are technically insolvent. Did mtgox suspend BTC withdrawals in order to prevent a run?