I'm quite concerned that during the last week while mtgox has been down people have been very actively stealing wallets. We've seen many trojans and other wallet collection scams. Perhaps people took less care to make sure wallets that had little/nothing in them were not stolen.
If someone made a copy of your wallet this week they may be sitting on it hoping that when mtgox comes up you'll withdraw all your BTC and as soon as they see that transaction they'll launch a matching transaction to give all that coin to them. Even if your wallet had nothing in it before, if someone copies your wallet they will also gain access to future payments to the addresses in it as well as 100 future addresses (which are pregenerated and hidden).
If there is _any_ chance that your wallet has been compromised, do not deposit a bunch of coin in it. Instead make a new wallet or cycle out your old keys by hitting getaddress 101 times before using the next address. Make sure to update your backups too.