Fast and simple answer is the ECS K7S5A motherboard. It seems to be the "hot item" around here for now. Very Inexpensive (cheap!) but great performance and would give lots of headroom for future expansion for your co-worker. Do a search for it on this forum and you will find numerous threads about it. You can buy it
here and
here. It would fit your criteria like a glove. ECS has always been known for providing low cost, stable boards. There may be even more places carrying it now.