for amd the asus board on the kt266a is the best
Personally, I'm going to have to disagree. I've heard of many problems people have had with that one. A person I know has that board, and it's been quite unstable for him.
I'd say that for the KT266A Athlon/XP/Duron platform, EPoX 8KHA+ and Abit KR7A are the best.
Oh, the little things: Asus A7V266-E only has 5 PCI slots. Both the EPoX and Abit have 6. It's not too big of a deal, but still, 6 PCI slots make a board look like a much higher-quality product, IMHO. Same with the 4 dimm slots that the Abit has.