The Core 2 Quad at 2.4 GHz is currently the best selling quad core of our time, mainly due to Intel’s recent price cut.

This 2.4 GHz CPU costs an affordably €250 and a lot of users are getting one of these. The good news is that they are overclocking great and that you can hit much higher speeds at not so much money.

The biggest trouble is that in current games and 90+ percent of applications you won't see any benefits from going from dual to quad core, but it might make you feel better if you run on a Quad core.