Need setup recommendation

I am seriously considering going back to water cooling. The new components seem a lot better than the old heater core and brick of drilled aluminum I used back in 2000.

I am looking at cooling the following.

1. Conroe 6600 - Overclocked
2. nVidia 7950
3. AMD 64 3000+ - Not Overclocked

This will be 2 systems in a single enclosure and I would like to keep the noise and power consumption as low as possible. The water components will all be just about level with each other (no real high area).

Could a single 3x120 rad handle this load or would I need to run separate loops? If so, what pumps do I need to look at?

Guess I should to try to be more clear.

Though simplified, would either of the following loops work? Any suggestions? I would like to keep it down to a single pump and 3- 120mm fans.