I would go with a XFX 4870
and a Crossfire MOBO. You want to avoid a Nvidia chipset motherboard (750, 780, & 790), if you can. These boards are not known for their reliability.edit
The E7500 will not be a bottleneck in gaming. Also, have you looked at an AMD Phenom x2 550 AM3 build? Can be built close to the E7500 build but provide an upgrade path down the road.