<< MSI 6340M is definitely a good choice, rock-solid stability, KT133A chipset, no problems.
Another possibility is Soltek 75KIV, very similar to MIS 6340. >>
The ECS will probably be a bit cheaper, but I've also had excellent luck with the MSI KM133 board. Excellent stability. I've used them to replace a bunch of old Pentium boards at work and they're all running great. NT drivers suck, but Win9X, 2K work fine. Also, I'm actually typing this on one in WinXP and it works great. Don't know what the video drivers are like in WinXP though since I have a Radeon in there.