What MOBO goes best with the rig im building??? Please help.

With this kind of rig , i'd say that you have to wait for Core i7, for many reasons:
("i7 800"=2.6Ghz , 4 cores;8 Threads) and for the price its listed;284$ (or expected to be lower than Q9550 which is about 350$ .

Core i7 uses triple channel ,meaning that it will use the full potentials of DDR3 unlike the current DDR3 thats in the market right now.

and last you'll use X58 chipsets its brand new , plus gives ya the capability to over clock each core independantly(thats if you want to overclock) on top of that intel claims that each core overclocks it self automatically based of process power you want

hope this help ,

Cheers

i would recomend a x38 or x48 mobo.
Or look into nvidia chipsets if you ever plan to go the SLI way.
I think ASUS gygabyte and MSI are the best mobo's out there

Chook is right on here. P45 is great for overclocking and stability. Check out the ASUS P5Q Pro or the Deluxe.