This is how much it costs in electricity to run my 13″ MacBook Pro per year, if it were continually left on: $11.20. My 32-inch flat screen TV? That’s a whopping $100/year, if left on; but when it’s off, it’ll only drain to the tune of about 75 cents per year (similarly, my MBP only drains about $2/year in sleep mode).
How do I know this? I’ve been (lame-pun alert) charging around, giddily testing everything in the house with Belkin’s Conserve Insight, a brilliant, $30 tool that measures the energy use of any gadget or appliance that plugs into a wall outlet — and the results have been (oh, and again) electrifying enough for me to really change my habits.