Hi newcomer and welcome to the Tom's hardware forum.
1- What is exactly ur budget?
2- Do u want OC?, because if u don't want it u can get the Phenom X4 945 and go with a 5850 that is a very good GPU.
3- Two good options for ur rig are this:ASUS M4A79XTD EVO and the Gigabyte 790XTA-UD4
But please post ur budget, because best can be the ASUS Crosshair IV ($229.99) or the Gigabyte 890FXA-UD5 ($179.99)
Unless you have a need for for USB 3.0, this motherboard will be fine. It is even compatible with the new thuban 6-core CPUs.
Also, I agree with saint19. The GPU should be your priority. Unless you are planning on a 5870 or better, Don't bother with the phenom II 955. The best CPU you can get for the price that will be fine for you is the Athlon IIx3 440 at 3.0GHz. Spend the rest on the GPU.