All the motherboards are typically about the same in the performance with the same chip set and processor.
-What type of video card are you going to purchase?
-What are you going to use the computer for?
-What speed is the ram you have?
-Are you going to overclock?
Here is a motherboard right from Intel that leaves you some upgrade room if you ever do. You could have Crossfire with this motherboard if you choose, but SLI is out. Not as though it matters to me, The thought of buying 2 video cards only to have the next generation out perform last generations 2 cards doesnt sit very well with me.
http://www.intel.com/products/motherboard/d975xbx/index.htm
Oh and by the way how do you get a processor first and not a motherboard???