I just ran across this application and I have to say that I'm loving it so much I want to share it with everyone. It's called
Game Booster by IOBit. What it does is it temporarily turns off unnecessary services such as Windows Search, Search Indexer, Print Spooler, IP Helper, etc. while you are gaming. It increase my performance by around 5-10%. I like it mainly because of the obvious performance boost and I don't have to manually go to each service and disable it myself. I actually like Windows Search/Search Indexer, but it interrupts my gaming experience because it uses so many resources. I like how it disables everything for you, then when you're done gaming it re enables all the extra crap.
Using this and ReadyBoost really helps performance on Windows 7 64-bit. At least for me anyways.