In this order
1. CPU cooler, the corsair H100. Curent: Stock LGA1155
2. PSU Corsair AX850, or Seasonic X850 Curent: OCZ ModXtreme pro 500W
3. A second GTX470 or a next gen card Curent: Single GTX 470
4. Crucial M4 64GB SSD for SRT
5. An Ivy-Bridge CPU Curent: I5-2500k
6. Another 2x4gb sticks of corsair 1600MHZ vengeance Ram
7. Watercooling.
8. Faster network, 3MB/s atm.