What I did, was go to Mwave or newegg.
Look at motherboard bundles for the processor you want.
Pick the speed of the CPU, ie 3200, etc.
Then look at the motherboard options listed.
There should be a long list of available motherboards for that processor.
Copy, paste into google, and read up on the board.
Process of elimination till your down to one that has what you want, that you can afford.
There are a LOT of good boards out there for 50 to 120$ I don't see much need for going a lot beyond that in price.
Mwave will even add ram, and for 9$ assemble and test the whole bundle.
Its the cheapest insurance you'll ever pay to make sure the vital parts are all going to work when you drop it into the case.
Plus you can not put together a combo that won't work.
Drop it into the case, hook up led & switch wires, power, ide/ata cables, and your ready for drives & first boot.
PS I'm partial to Abit boards, virtually no jumpers to set, its all done in bios software. So they are very easy to build, very reliable. My oldest abit board finally failed on me last year after a power surge. It was 6 years old and had been in 3 diff cases/configurations.