Here is my consensus on the currently available KT266A solutions:
ASUS & ABIT:
The releases of their boards are too recent. To consider either one would require some waiting for the prices to drop.
Shuttle:
This board is great, and it costs very little. It is not the highest performing or the best overclocking. However, it does come extremely close. The differences are almost negligible.
EPoX:
This board is for pure speed and overclocking. If that extra bit of performance and tweaking power is of interest to you, then by all means the extra $20 is not too much.
MSI:
It's a little lagging in performance in certain situations. The overclocking is also not quite as good as with EPoX's solution. Again, these differences are minor and almost negligible however. The RAID and USB2.0 variants are good if you are going to take advantage of these features.
Soyo:
This board is great, the only problem is that it includes too many things onboard. If you need the included equipment, then it is a good buy. However, if you do not, then get a more basic motherboard.
All boards seem to be very stable currently. If you want to make sure of absolute stability, really do some research to find out how the boards are designed. Look at their capacitors, and see if they accept voltage mods for absolute overclocking stability.