If I was buying a nwe mobo I'd probabaly go for nVidias nForce 415, performance equal to the KT266A, and users report great stability and drivers.
And Asus' K7N266-C has one erally nifty feature, even if you overclock the FSB, it will keep the AGP/PCI at 33/66 MHz, making the CPU and memory the only bottlenecks, great for overclocking.
On a sidenote, I have no problems with my KT266A based Epox 8KHA+.