The GTX 650 is not that good. The Radeon 7770 is far better for the exact same money. And I'd pay a bit more and get 8GB of RAM, otherwise that's not a bad build at all for the money.
Okay. How does the Asus Nvidia GTX 550 ti compete with the 7770? I am limited to 4 Gb Ram because of my operating system. Otherwise, I would definitely have 8 GB.