Before I got Comcast setup in my new apartment I had to use my T-Mobile Blackberry tethered to my laptop. In just one night of streaming Al-Jazeera over that I used 2.5 Gigs according to the meter on their site. But once I got Comcast setup I tested it with their meter and it came nowhere near that much usage. I don't know how to call them on it thought. Can their really be that much overhead on a mobile connection compared to a cable one?

Just get a Kill-A-Watt. My desktops use about the same power as a lamp with a 75 watt bulb in it, my laptop is 20-30 watts.