If you wanna save money get the G.Skill DDR2-800. While corsair is a better name I've rated this ram to go to 540mhz+ on an accidental 2:3 fsb ratio. I have mine currently running at 450mhz at 5-5-5-12 no problems.
Like I said corsair you pay for mainly the name these days and maybe a bit better quality, but for the price and the speed of this ram you cant go wrong. Heres a link to cheap but good RAM that will run as high as you want it at good timings.
Dop you remember the best FPS for your buck topic I made? I told you that in a gaming PC RAM should should be the last thing you try to buy thats better than average. Take the 60 bucks youll save on RAM and buy a good sound card or even the E6400 with its extra multiplier