One other example of a situation where RAID 0 might improve performance substantially is in certain games. Usually, first person shooters are not part of this list.
So, how do you tell what games might benefit significantly? It isn''t easy unless you have some knowledge of how the game works internally. For example, Interplay's "Baldur's Gate" series, as well as games based on the same engine (Planescape: Torment, Icewind Dale to name a few) benefit from RAID 0 because the levels that they load are essentially huge bitmaps. Because the hard drive is reading one large data file in a linear fashion (as opposed to the heads having to move rapidly back and forth to access many different files), sequential transfer rate is all but the only factor effecting loading speeds. Some other games benefit to a lesser degree.
As stated above, first person shooters rarely benefit from RAID 0.__ Frame rates will almost certainly not improve, as they are determined by your video card and processor above all else. In fact, theoretically your FPS frame rate may decrease, since many low-cost RAID controllers (anything made by Highpoint at the tiem of this writing, and most cards from Promise) implement RAID in software, so the process of splitting and combining data across your drives is done by your CPU, which could better be utilized by your game. That said, the CPU overhead of RAID0 is minimal on high-performance processors.
granted it's a minimal increase in speed and only in certain scenarios (i.e. certain games), but my statement isn't false.
edit: it's a hot topic for debate actually, and some empirical evidence points in one direciton and some points in the other. there's also the subjective inference by many who run RAID 0 after running single drives. regardless, it's a marginal increase in most circumstances, but i still hold that my statement isn't necessarily false.
edit 2: more links to read up on and make your own decision...just to show i'm not a stubborn fool...