Hmm, well it all depends if you want a quad or a dual core, which really comes down to what you are going to be doing. E8400/E8500's are great for Duals, as long as the Q9400's for a quad.
With the motherboard, I would pick up a p45 board for sure, such as a P5Q Pro or P5Q-E for crossfire down the road if you wish.