Hopefully somebody with Saitek gear will jump in here. I thought they had new software that worked with 2k/XP?
Anyway, RAID 1 is mirroring, RAID 0 is striping. Mirroring brings no performance gains, it's just that you have an identical disk as a backup in case one fails. RAID 0 is striping, and it will bring a performance improvement, mostly on the read side. The more disks the better.

Ideally you want higher versions of RAID that include the striping and fault tolerance as well, but those are much more money and usually SCSI based systems.
Should you get a RAID setup? Well, it depends. If you want the mirroring for data safety, then that's a cheap way to get it and you don't have to do backups. For performance... well if you do things that wait on your hard drive all the time, then you may want the increased I/O performance. Video editing would probably be something that would be an application that a stripe set would really help out. Personally, I think for gaming, you are better to get a good quality mainboard and HD setup from a value standpoint. Go stripe set if you have the need for speed, but I don't expect it will make a big difference. I'd make sure you've got a fast machine and a GeForce 4 Ti before I put extra money into RAID. If you have a mobo with no RAID controller, you can always ad a PCI RAID card in later if you get the urge/money to do it.