P9X79 or RAMPAGE IV EXTREME

The Rampage IV Extreme is hands down the best X79 board out there, but it is a bit pricey. If you can afford it, you won't be disappointed.

Unfortunately you can not use DDR2 memory in a DDR3 board since they use different voltages, timings and physical sockets. On the plus side, DDR3 memory is really cheap right now :)