I'm not quite sure how to answer the poll. I bought an Asus P2B-F back in '98 (for my 400mhz PII), and it's been rock solid ever since I first put it in service. It's now my backup Linux box.. On the other hand, I've recently purchased an Asus A7V266-E/Athlon XP1800+ combo, and it's been rock solid as well.
I'm giving my PII machine to my brother, so I may soon be in the market for another PC. I'm not sure if I'll go the Athlon or P4 route, get a PowerMac G4 (!), or wait for SledgeHammer (or Opteron or whatever they're calling it this week).. It probably won't be the Mac, though..