Abit is the most reputable of the lot. Epox didn't do a bad job either. If I had the money, I'd get the abit, then the epox (My Mobo is epox 8k7a and it is working great). They still say the kt266 hasn't matured yet, but they said that about the ALI too.
We should see lot of new motherboards based on the SiS735, nForce, and KT266E (revised stepping) soon. But if you want a mobo now, I would get an AMD760 board and IMHO the Gigabyte GA-7DXR (about the same price as the Abit KG7R) is the very best one out there!