I agree, the laptop method is appealing. But not really my style. I've ordered this:
For more info on this thing click here .

Yes, I'm nuts, it's expensive, it has everything AND the kitchen sink, but a mans got to do what a mans got to do. Besides, you cant go wrong with a full fledged PC that fits in a 7.79x6.33x2.44 space. To my credit I did NOT opt for the CDRW/DVD combo drive. See? I can practice restraint! Anyhow, since all the relevant connections are in the back I can make a quick connect docking station of sorts and have the unit "plug in" somewhere. Right now that somewhere will be under one of the front seats. I'll stash the 7" touch screen in the console when I don't need it and I'll use a goose neck mount to hold it in place when I do need it. I'll need a power management unit to control the thing seeing as how I plan on wiring this directly into an outlet that's always live.

Another idea I've got going is setting up a wireless hub in the car somewhere. Yes hub. My reasons are entirely to nerdy to list on this fine site but suffice it to say that this would be killer when getting together with a bunch of people out on a trail equipped with notebooks and WiFi adapters.

Now to order the screen! There was a bit of an uproar from some people on MP3Car.com. They had a group buy on the Xenarc 700TS and several of them had complained about poor quality/service. I'll have to look into that a little more carefully before I settle on that model.

On a side note, I had really looked into using a laptop as a car computer but several things turned me off. The inflexibility of the hinged LCD and computer kinda bothered me. You couldn't just mount the LCD where ever you wanted. It's also a little bulky and I'm really looking to have this thing be as unobtrusive as possible. Laptops definitely have their merits though! The easy full system portability and battery option are just a few. I had to do some weighing of wants/needs but in the end...well, you know.