Don't even think about that Enermax if the requirement is "good coolling". Those vents on the back are aweful and the fan on the side panel doesn't even line up with your CPU.
Go with any of the Centurions:
here
You may need an additional 120mm fan. The metal mesh front is GREAT for air flow, and the side panels line up w/ the components that need air... i.e. CPU and video card(s).
You can get one pretty cheep enought to get a decent power supply, but you will probably have to go higher than your $120 cap.
The Sonata is a great choice too, w/ a very decent PSU, but it's not quite up to the 500Watts you required. But as long as you stay away from SLI or Crossfire, and muliple hard drives and opticle drives, you should be fine.