Which motherboard for new build.

Thanks to massive overtime from the RNC, I am finally going to be able to start purchasing the meat of my new computer build. I was thinking about getting a different motherboard that I originally was going to get, but thought i'd see what everyone else thought first (I am a first time builder)

Here is the one I am thinking of getting: http://www.newegg.com/Product/Prod [...] 6813131299

And the one I was going to get: http://www.newegg.com/Product/Prod [...] 6813131275

The reason I am considering the change is because of the PCI-e x16 slots. I want to be able to fully utilize cross firing in the feature.

Incase it helps, here is what else I am getting:

Case: NZXT TEMPEST Crafted Series CS-NT-TEM-B Black Steel / Plastic ATX Mid Tower (already bought)

GPU: HD Radeon 4850

CPU: Intel Core 2 Quad 6600

RAM: CORSAIR 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model TWIN2X4096-6400C5

Optical: LITE-ON 20X DVD±R DVD Burner Black SATA Model iHAS120-04

PSU: Corsair 750 Watt Power Supply (bought)
And I will be doing Vista 64-bit.

Any other suggestions on the build are greatly appreciated, just note that I am trying to keep the cost around 700 to 750

edited my post to include the PSU I already bought, thanks for bringing that to my attention

Thank you for your advice. I went with the P5Q-E and also upgrading the RAM to the suggested 4.0-4-4-12 800