I have the same problem....I withdrew yesterday and it still hasnt arrived! nearly 24 hours now.....nothing. Not in the blockchain at all. 4.72BTC. This is ridiculous, Mtgox are so terrible..... support tickets go unanswered not even 'allocated' to a customer service rep yet.
Sorry to hear that, but being optimistic is a good thing and those BTC will show up soon, like OP's BTC.
Luckily the market is rising now so they're appreciating in value, that is if I ever see them. Still no sign of them 2 days and counting now, no answer from support.
I like to threaten them, come up with some ideas to do to their business if they dont give you your BTC, They locked me out of my account back when they accpeted USD, and I gave them proof and they held $487 and 3 BTC. I contacted them back and told them I would take legal action to get my money back because they still asked for proof of residency and coming up with stupid excuses for them not to verify my given info.
So 4 days pass and they finally open my account, success, success,success.