I have a Garmin Street Pilot, about 500 bucks on Amazon. Its not really portable(as in stick it in your pocket) but can be moved from vehicle to vehicle and does have have batteries so you could use it walking I suppose. I wouldn't trade it for anything. I could get lost in a closet [Linked Image] so its great for a direction challenged person such as myself. I got it to go to Milwaukee. It was a life saver as they are doing a huge amount of construction on the major interchange in the city. Got to the Bradley center, Miller Park and all around without too much trouble even though many exits were closed and detours were everywhere. Can't wait to use it in Boston [Linked Image]