I have money on both exchanges but what's the point if I cannot cash out the profit from Gox and with that profit buy more BTC at a lower price on Bitstamp?
The only thing I can do is to buy coins at Bitstamp, send them to Gox and sell them at a "profit" that I cannot realize for weeks/months. When I realize that profit, I can buy way less BTC than I could have bought if I could have transferred the fiat fast (I'm assuming BTC is raising mid-term, as usual). Making a long story short, I will make some $$$ because I'm buying on Biststamp and selling higher on Gox, but I'm losing coins because when Gox's profits arrive and I want to buy more coins the price on Bitstamp is HIGHER than it was on Gox when I sold.
That's makes arbitrage pretty pointless to me - and I guess than for many others too, otherwise there would be no constant and big spread between the exchanges.
A less greedy solution is withdrawing BTC or if you have USD: buying BTC at mtgox and then in both cases withdraw all BTC from them. Those BTCs could then be put in safe storage and the risk of losing them is much lower than leaving them at Mtgox in my pov