I have a Garmin Montana and love it. It's somewhat ruggadized and water resistant (but not completely water proof), so it has no problem surviving in my jeep. And it can run on either the rechargeable lithium batteries or AA's, very convienent if you're going to take it backpacking. And compared to all the little handhelds, the big touchscreen makes using it in a jeep much more convienent.
In addition to the pre-loaded topo's, put the road maps onto it, without that map package it can't do the normal street directions.
And if you get the motorcycle mount, you can directly screw it into the dash, and the GPS firmly snaps into it, with an extra little security screw to prevent stealing it. And it's got a built in charger that you can hardwire into the jeep. The mount also comes with a couple screen protectors, highly recommend using those for that big touch screen.
First downside, the built in camera is shitty. Although a little picture tag shows up on the map where you took it, and you can click it to see the thumbnail. It's convienent if you want to remember where something is, snap a picture.
Only other downside I can think of, when you're doing street directions, it doesn't show distance to next turn right on the map, you have to click to see the list of directions to see the distances.
