E6850 is expensive and obsolete. Go for E8200 with overclock, or E8400 without overclock.
P35 motherboards are plenty. The best one in the high end segment is the Abit IP35-Pro.
A lesser and more mainstream board is the Abit IP35-E.
both are brothers, with the former being the enthusiast's and overclocker's delight, and the later being a power hungry hole in the wallet guy's delight.