I carry a laptop. Jack power from my cigarette lighter, audio through my Sony head unit, and on ocassion update my Garmin on dash GPS on the fly thru serial interface. I store tons of mp3's on my HDD. Got big screen LCD for watching DVD (15" standard xga laptop display (LOL)). Total cost... not one thin dime, just using stuff I allready had , and it all fits in a brief case out of sight, literally and goes where I go