I'm not sure who all has read this article but I think it's a great read:
It says, basically, that the wii uses 'a lot' less power than PS3, XBOX360, or PC. It also uses 5X as much power when wiiconnect24 is turned on as opposed to when you have it in true 'off mode'. (I made that term up but I think you understand).
I've had my wiiconnect24 off for a month now and don't regret it, it's a feature that simply isn't worth the dollar a month worth of power... I really couldn't believe that the wii peaked around 18watts while the other 3 were all peaking around 200watts. I mean the graphics of the other three are better, but not 10X better!