I like to go with the smaller guy usually. Hence, I am an AMD fan. Athlons are totally stable. The chipsets out there are another issue, but most of them (now) are stable. I wouldn't hesitate to use VIA, SiS, ALi, nVidia, or AMD chipsets with an AMD CPU. They are now mature enough to be very stable.

That said, you can't beat Intel, on Intel, on Intel (Intel CPU, chipset, and motherboard) for stability. Intel boards are now becoming options again now that they're making boards with features. Even though I say that, I am currently running a P4 with VIA chipset as my main machine. It is rock solid despite Intel claiming VIA doesn't have the rights to make a P4 chipset. It also happens to be very inexpensive.