Have some extra parts to build a PIII or P4, any reco's on a stable MB

I recently put together a couple economy systems using ECS K7S5a boards but couldn't get them to work with my PC100 SDram, had to go DDR.

Now i have two 256mb PC100 SDRam sticks, an Enlight 300 (which also wouldn't work w/ the ECS), along with some other components.

I am not AT ALL familiar with Pentium boards but am considering picking up a mainboard and PIII or P4 cpu that I can utilize this SDRam etc with. Looking for something good and stable but more of an economy price range.