Harcoreware.net has an interesting article on-line today that details the power consumption characteristics of today's top three new consoles while playing back video and playing games. And for the sake of comparison they also built a mid-range gaming PC to see how it stacked up.
The disparity between the Wii and other consoles is amazing. And how about that PC? Looks like the XBox 360 and PS3 consume quite a bit of power.