Is it possible?

Having recently upgraded both CPU/motherboard and graphics card, I'd say whatever you do as your base, go Intel. My two systems before that aimed to save money on the CPU and spend more on the GPU. Seems that for actual play and frame rate and whatnot, the CPU is far more likely to become the bottleneck at low prices. I'd find it hard to put something together for less that 800, especially if you aren't reusing a lot of drives and your monitors.