I'm not a big fan of gauges because it'll tell you you need air, but then what? I keep a rechargeable pump beside my bike and after every coupla rides/weather change while I warm up the bike, I'll check it and pump as needed. And for long trips I can either take it with me or swap it out with the cigarette adapter.
http://www.topoftheline-travel.com/c...r-station.html
helps that I got it on sale for $20 though.