Never underestimate the power of trolls on the internet.  You didn't think it was solved, or you would have withdrawn earlier, right?  Trolls have been feeding a zombie epidemic.  People are seduced into believing in crazy stories about millions of USD mysteriously disappearing from MtGox.  The people become zombies who buy BTC on MtGox and sell at a loss on other exchanges to "secure their money", and go on to spread the epidemic further.  This is very profitable for the trolls who cash in large amounts on arbitrage by doing the opposite of the zombies.

Equalization takes time.  Right now there are bids for 14439 BTC on MtGox at Bitstamp price or above.  That's more than the entire order book on Bitstamp, and a lot of money has to move before the price is equal.