@hypergamer,
Overclocking a Q6600 to 3.6GHz+ wouldn't help much in synthetic benchmarks or gaming. You'll be actually compromising your RAM's frequencies too with divider settings. IMO, upto 3GHz for a Q6600 model is sufficient. Anything above then that, then opt for i7 series processors. They actually have better fabrication technology too.
Anyways, for Liquid Cooling, i would suggest cooling kits from Thermaltake BigWater series. If, they aren't available, then you've to settle with CoolerMaster's Aquagate kits. Good Luck..
@chicane,
Windows 7 packs far better Direct-X features, several video enhancements, better resource utilization algorithms in comparison to windows xp. See, as far as experience is concerned, both XP and Windows 7-32bit scores quite close to each other.
However, you've better hardware and technology. So, try gaming with Windows 7-64bit with >4GB RAM and faster CPU instructions, and you'll see the performance is far better than XP. Moreover, you'll realize gradually that 7 is actually more stable with games than XP.