MSI P7N SLI platinum mobo with the Intel q6600 is your best combo
I actually ran a very similar setup as one of my first builds and worked great!! (I ran with two 9800GTX's after replacing the my 8800 GT). I upgraded to a Q9550 and handed the PC over to my Dad to replace his dead PC. For a heat sink, I would look at the Sunbeam CCTF for the LGA 775 socket. It is a great cooler at a good price.
If you plan on running a GTX 470 and an 8800GT, I would highly recommend going with at least a top tier PSU, such as Corsair CMPSU-650TX (will need an adapter for the 8800GT though).