Same here. I'm wondering what Mt.Gox's influence will be on the daily profit.
So far it's rather good because the price has been extremely fluctuating yielding to 1.2+% daily profit, but I'm wondering how they're going to compensate for the frozen (stolen?) money they had in this exchange...
I think that well executed arbitrage trading on an emerging (so fluctuating) market such as Bitcoin is highly profitable (supposing the exchange does not lose $350M -_-). When the market will be less volatile and stabilize, we will for sure earn less because the price difference between exchanges will be much less.

My strategy is different, I am buying as many shares as I can with the daily generated profit in order to have a compounding effect. When my shares will expire I will cashout the money I invested and only will use the money earned by the profits. Following this I am planning to daily cashout half of the earnings, and reinvest the other half to compound further. Doing this is a bit more risky than cashing out everyday (because for 4months you are basically not earning anything), but yields more money with the compounding effect.