It depends on your needs really. If you do things with your computer that require a lot of read-write operations to the hard drive like recording high quality audio or encoding/video editing RAID will most likey help. But keep in mind you'll spend much more cash on hardware and also add more complexity to your configuration. (
Could complicate data retention in the future). Depending on your needs, you may be better served by a single high speed drive like a WD Raptor 10,000 RPM.
You need to determine the value to you:
Price vs. Performance.
I would recomend doing as much research as possible on the subject of RAID. And you'll learn there are many different configurations available such as RAID 0, RAID 1, RAID 5, and so on.... You really need to understand the pro's and con's of each to make an accurate assesment of your needs and how best to meet them.
As far as gaming goes, you'll see improved load times for games that load a lot of data from the hard-disc ex:Half-life 2. But the frame rates will be the same, you'll just get there a little faster as a result of faster file transfer rates helping Windows and in turn said game run a little smoother.
But again you can buy a fast single drive and get reasonable results and save some cash for Memory or a better GPU or CPU or something..
Personally I have a machine with a RAID set that I use for Audio and Video recording. My gaming rig has 2 SATA drives no RAID.I Play FPS games like Quake4 and Doom3, my SATA II drive is fast enough for me. In fact sometimes I don't have time to sip my coffee between maps
.Also if your motherboard doesn't have a RAID controller on it you'll need to get a controller card too.
Dang, I gotta type faster lol, by the time I hit "Submit" theres a slew of responses. :lol: