MSi K7TPro2 if you want multiplier adjustments K7T Pro if you don't care.
The MSi baords are great stability/quality (Anandtech's webservers run on MSi K7TPro boards). They are alot cheaper than their Asus/ABit counterparts. The Asus board has to adjust the multipler with DIP switches, and while the ABit has software adjustment as well, the whole ABit Quality Control/RMA/Tech Support issues cause me to steer clear of ABit if I can, in this case the MSi K7TPro2 offers all the featurs of the ABit, at a lower price and with better tech support, should you need it (and without a $25 RMA charge, though an MSi board is less likely to need it).
All in all the K7TPro2 is hard to beat.
If you want SlotA there really aren't that many great motherboards...Asus K7V is probably the best slotA...but you should definately get SocketA unless you have some specific reason not to, and the MSi SocketA baords are excellent.