I have a similar setup:
Tyan Tiger, twin XP1800, Highpoint Raid, 2*Deskstar 20G, 1*deskstar40G (backup), 512M crucial DDR, Matrox G550, 3COM NIC, Win XP Pro.
I am using unsigned drivers for raid, ADSL, ISDN, and camera. (signed ones not available)
The system is utterly stable even with uP temps...