The problem with this approach is that bitcoin is an extremely volatile currency.
Your approach may look good on paper, but it's very difficult to time the market to make any profit. MtGox DDOS attacks are also not helping.
Plus getting USD into btc-e will cost you at least 2% of your principal. Not to mention plethora of other fees.
Actually, the volatility is not the problem. BTCe stays consistently $5-15 under Mt. Gox spot. Why? Easy. It's hard to get USD into BTCe. The price reflects that. If it were as easy as getting dollars into Mt. Gox, there wouldn't be a spread, due to those taking advantage of arbitrage. Most people who have USD in BTCe have it because of a trade out of a cryptocurrency into dollars. They can arbitrage all they want, but they most likely (not always) lost money while getting into that USD position. If it were easy to move cash into BTCe, there wouldn't be a spread, because the free market would arbitrage to the point where the amount of the spread is negligible.
