Intel Core 2 Duo E8600/E8500/E8400 and Intel Xeon E3110 are the best gaming chips out right now. No other processor, at a fair budget, will outperform these in gaming. You can buy the Core 2 Extreme chips that are also great, but overpriced. BUT, if you're not one of those who have the money to build a new computer every 6 months and you want a good computer that is future proof, your best bet is to go with the Core 2 Quad Q6600. As stated previously, it can be OC'ed quite high. I think 4GHz is only achievable with liquid cooling.