That said, a new/faster HDD can make an older computer seem really fast. Plus, $70 is a great price for the F3. So if you need/want more storage space, buy one. If you're only doing it for gaming performance, don't bother.
Agree, all a faster harddrive does for a game is to speed up loading times. I'm running my system on two 7200rpm 1.5tb drives with 32mb onboard cache in raid1 (for redundancy) and the system is more than quick enough. There is no need to go high risk raid 0 or expensive 1+0 (or 0+1) to play games. A single quality drive is fine.