it would be better to do a dual hard drive setup and run them in RAID1 or 0 but, if you have the extra money, you should at least consider getting 2x74.6Gb 10000Rpm "raptors" from Western Digital, they are AWESOME! of course run them using RAID1 or 0, that would make your system considerably better, not that it needs it
. your CPU looks awesome, i would recommend getting this
motherboard, i dont think there is better ram for the job, I would also recommend getting a Thermalright XP-120 Heatsink
it doesnt come with a fan, but with the recommended fan, that thing would keep your CPU nice and cool
. like everyone says, go with the 6800GT.