I tried to log into my MtGox account today only to be told my username/password didn't match.
As I recently changed the password, I assumed I typed it wrong and would just do a reset. So I entered my email/username for a reset and was informed that my email address was not on any account.
I've filed a ticket and I'm waiting to hear a response back from MtGox now, as I had about 25 BTC in my account.
Likewise, when I told my friend about this, he had me log into his account to withdraw his bitcoins. When I attempted to withdraw them, to his wallet ID, I was given a new message I've never seen before.
Apparently, MtGox is now limiting the amount of BTC you can withdraw from your own account. I understand that due to recent posts about accounts having missing BTC, it's likely for security purposes, but if MtGox isn't letting me withdraw my own bitcoins, I see a major flaw in this system.