Hi
fadedhearts, what parts do you have that you'd like to re-use? Particularly memory and power-supply unit.
If you have PC2100 DDR memory or above, then you might consider the EPoX 8RDA+ or the Shuttle AN35N Ultra. The Shuttle is currently under $55 at
www.mwave.com, the EPoX is coming in the low $80's right now. The EPoX has the fancier version of the nForce2 southbridge, giving it Firewire ports and an upper-end onboard audio processor. The Shuttle lacks the Firewire and the extra-nice audio processor, but it's hard to argue with an nForce2 Ultra 400 board for under $55!
If you've got PC133 and want to re-use it, an ECS K7S5A Pro or K7S5A would be a couple possibilities, except don't expect too much from the onboard audio.