Single desktop computer with:

  • i7 920
  • nvidia gtx 260
  • 9gb ddr3 ram
  • 1 3d ready 1680x1050 22" lcd; 1 2048x1152 23" lcd 
But you don't need 9gb or an i7 to 5 box; I used to 5 box fine on a beefy laptop with 4gb
Comcast - need a lot of upstream bandwidth for streaming - here is a recent test with 2mb/s streaming live ongoing, on a busy weekend:
 w/o the stream :