A few corrections for coelacanth. Each of the cores in a multi core chip runs at the stated speed. Thus, all 4 cores in a 6600 run at 2.4ghz. For some games, the dual cores may be faster, but for the future, a quad core is better.

My PC is built on an Antec 900 case, EVGA 780i motherboard, 4GB DDR2 RAM, Q9300 quad core overclocked to 2.8ghz, and I may be able to get it up to 3.2. CPU cooler is a Zalman, one of the big round copper finned jobs. Video is an XFX nVidia 9600GTS. Hard drives are a 150gb WD Raptor and a 500GB WD standard drive. Monitor is a Samsung 2053BW, a great monitor. I can play Bioshock, Portal, etc at full resolution and most features cranked up to max. Crysis isn't as fast as teh others, but that's true on any system. Crysis does use all 4 cores.