P2, P3 and ealier P4 (1.6G) I used Gigabyte (no OC), stable and no problem at all, every MB stays alive when I wanted to upgrade (2~3 years).
K8, I bought ASUS K8V-X first, 90% OST capacitors; don't want to take the chance of the reliability. Changed to use Abit KV8 pro, and am using now (1 month so far, try joining the OC team). Need longer observations.