Will this computer system all work togeather?

That should make for solid gaming PC. I would go with at least a 850 watt PSU, in case you ever want to add another GTX 470 for SLI. Also that I7 has a tri-channel memory controller. You'll want 3 sticks of RAM for the best performance. You'll want 3x2GB sticks for the RAM configuration. 3x4 GB sticks will also work, but it's probably overkill. If you fill up two or four of the RAM slots, you'll get reduced performance.