RAID array really do offer anything to gaming.  They may help with large load times in games, but unless you're working with large video/photo/3d stuff, I wouldn't bother too much with RAID.
My current setup I use RAID 0 because of the above.  I benched with 1 drive and later on with 2 drives in RAID and the numbers and performance were a good improvement.  At the time, for price/gb size, it made sense for me.  When those drive(s) fail, with current pricing on new HDs and performance gains, I'd stick with one drive.  Or go to RAID 1.