Check out Mwave or Newegg.
They have motherboard "bundles" they'll put together for you.
You pick the CPU, Mboard, ram, etc. Mwave will even install & test it for a measly 9 $. Darn cheap insurance that its going to run IMO.
So when it arrives you have a motherboard ready to drop into case. Hook up power, led & switch wires, ide or SATA cables, and Poof, your done.
The last one I built took a half hour to drop together. Another hour to load win & mboard drivers, and it was up and ready to rumble.