Can anyone tell me how many watts the CPU & GPU draw?

May seem like a funny question but I am trying to calculate (accurately) how much heat is generated by these chips for a cooling application.

Any info is greatly appreciated.

Considering high-end PC hardware I would estimate around 350 - 450W, Since the architecture is gonna be way more optimised.

I thought it was 160 watts.....

It might very well be. But considering the CPU has 3 cores and 6 threads and the GPU is more powerful than an X1900 I would say the minimum is around 240W.. IMO.

My Xbox power supply says "Output: 203W", so at the very maximum the Xbox 360 will draw and dissipate 203W of heat from its internal components.

The highest AC power draw I have been able to achieve with my Xbox 360 is 180w (this was while playing Gears of War, which most will probably agree is a very demanding game, maybe the most demanding currently available for the 360). A reasonable assumption for power supply efficiency would be 75%, which means the internals are using about 135w. DVD-ROM at full tilt probably uses about 20w. Power consumption of other components (such as RAM, hard drive, fans, etc.) should be pretty insignificant.

So I'd guess CPU and GPU power consumption, and therefore heat dissipation, (according to what I've read most/all of the power used by a CMOS device is converted to heat) is roughly 115w. Should be accurate enough for your purposes, at least.