RAID 0 from a price/performance perspective is not that great. I'm running dual 200GB 7200RPM WD HDs in RAID 0, and I could have certainly gotten a single 400GB drive for less. The array feels a bit faster than a single disk, but it's not huge and is really only noticeable at startup. I used to run dual Raptor 37GB HDs (the original noisy ones), and didn't bother to upgrade to dual 150GBs because they are way too expensive. I basically run A RAID 0 array because I want to, not because it offers some huge benefit.
btw, what does this have to do with video..? A RAID 0 array will not improve your fps...