Also, the faster the tranfer rate of the HD, the faster the computer goes. SATA is great for speed, and RAID configurations (RAID 0) speed up the PC as well. Also, RPM makes a difference. That involves access time, and the faster a HD spins, the shorter the access time is, which BTW is good.
BTW, Cobra, why are you still using Internet Explorer...................... EEEK! IE suks, and if anyone is still using it, go here and help yourself out!