That doesn't sound like it needs a lot of power, especially if this is a backup and you can live without HALO when you don't have the desktop. You may find some sort of netbook is enough. You do need to think carefully about power and price, though. For example, I'm guessing you won't be playing HALO on your drive to Vermount, but if you are away from a TV for a week, you might find you do appreciate having some entertainment in the form of games or DVDs.

I switched to a laptop this year. I agree with what others have said about price and power. This one is physically large and spends 95% of its time on a desk, as if it were a desktop PC. It's still convenient to be able to lug it to other rooms sometimes. It has a BlueRay player and a 17" screen, so it gets used for watching movies eg in bed. I've never taken it out of the house.

It uses a lot less electrical power than my old PC. I expect that's a trend with all newer devices, but laptops tend to be more optimised for low energy consumption.