many pps around the forums are pleased with the cheapness & performance of 80 Gb HGST (IBM/Hitachi) Sata300I've been running a pair as my os drives. £ Partiotions operating with XP Pro SP2, Vista 32 RC2& Vitsta 64.
See Nvidia Array Intel raid is faster
Once i've paid for my upgrade i plan to get another 2 of the hitachis' to speed up/try further raid options.
luck