Well, OK, if you don't have the Q9550 yet, go with roadrunner's advice.
Asinger93, why the heck are you telling him 780i for an i7 CPU? They're incompatible.
Edit: I guess Asinger93 was answering the original post, about the Q9550. Anyway, if you're going with i7 920 now then you need an X58 motherboard and a 3x1GB DDR3 kit.