The best way to deal with your laptop without a plug in..
Run the laptop batterry to nothing, turn it off, charge with the smallest invertor you can get away with (100 watt is probably about right) and then start the whole process over again.
If you charge with the computer off, it hardly makes a pinhole sized dent in your battery
I intend to try a usb TV tuner with mine, but I just bought a brand new laptop last week.. and it has Vista.. nothing works with it yet.
It really makes sense, since my laptop is always with me, and to buy a tv with that size screen that runs on 12v. would be .. well... expensive!