If you are going to reinstall windows, why RAID those drives????? If you are going to mirror them you've just lost the additional stoage space. You can do whatever you want but I would just use one drive for my os and the other for storage of critical data adn for back up. RAID on a home PC, in my opinion, is just a silly waste of time. But that's me.
Noli Nothis Permittere Te Terere!!
EVGA 680i, Dual EVGA 8800GT'S (650/950), 4 gigs OCZ DDR2 1066, Intel Q9450 at 3.8 Ghz, Koolance Water Cooled, Dual Plextor16x DL DVD+/-RW. Dual WD 250gb 16mb Cache Sata 3.0. 3DMark06 score = 19,168.