Go ahead and do the math and calculate the roundtrip time it takes to wire cash to btc-e - purchase btc - withdraw btc and deposit in coinbase - cash out btc and wait more time for cash to ach to your account and repeat. Add up the risks from volatility and all the fees in the process and you will soon realize that profiting from this is dangerous.
Exactly - when the USD prices on Gox BTC started to go up I knew that it was "time to remove all BTC from Gox" but plenty of suckers thinking that they would get rich from arbitrage stayed on until the collapse (and are now just hoping to get anything back from that failed exchange).