I read this: "A typical 14 inch monitor would consume about 80 watts."
and I was surprized to find out that other forums had no clue either...
although I read a reply suggesting that you turn off everything in your house exept your computer, then check the bill, but I think I would do it the otherway around...(ie: computer on, everything else off...)
good luck finding that info... you could look for a program that reads powersuply input... I couldn't find one