Have a Garmin 60cx that was a good all round unit. Haven't used it much since I got a more road friendly unit. Waterproof, rubberized, handheld unit, but had handlebar mounts and external power supply for the atv and motorcycle. Also had topographic maps to load for it. Great for hunting, hiking, canoeing, off road, or on road use.
Not sure what the up-to-date version would be, as I haven't kept up with them, but Garmin makes some good units.
Check GPS Central, GPS City, or Radio World.