You can probably sell the system with an OS for $600 without the water stuff.
Rough estimate.
- Asus Sabertooth 990FX -100
- AMD Phenom II X4 965 -50
- 2X4G Corsair XMS3 -30
- EVGA GTX580 + EK Block -200
- Corsair 120G Force GT -50
- 1T Storage Drive -50
- Corsair TX750 PSU -50
- XSPC EX240 rad
- Swiftech MCP655-B Pump
- XSPC Dual Bay Res
- ASUS Xonar DX PCIe Audio -50
- Bitfenix Ghost -50