m8, if you havn't ordered yet, i would seriously consider getting one of the new amd am3 socket 6 cored cpu's
Here is the bigger brother version.
http://www.newegg.com/Product/Produc...82E16819103849 6 cores each rated at 3.2 ghz... for $300 try getting a deal like that with intel. (intels response to this cost 1k)
Here is what appears to be a good mobo.. It has 4 pci e slots which means 3 gpu's for graphics and one for physics if you so choose.
http://www.newegg.com/Product/Produc...82E16813130274
Here is 8 gigs of ram. (PS im not up to speed on the latest ram trends so their might be a better alternative out on the market now)
http://www.newegg.com/Product/Produc...82E16820145284
As for GPU i would do whatever you believe is best. Both companies provide excellent products.
PSU make sure that it is powerful enough to power all of your toys and the such. Also just because it is rated at x wattage doesnt mean it will give out. Skimping on a PSU can bite you in the arse if you dont watch it.
Have fun and enjoy your new toy