Let me start my answer by telling you what's in my main two computers:
QX6700 & Q6700, both have an 8800GTX, 32 bit XP Pro & Vista Ultimate 64 bit, 2GB sticks G.Skill RAM (2X2GB & 4X2GB), Thermalright Ultra 120 Extreme in both, PC P&C Silencer 750 power supplies in both, Cooler Master 810 case...