http://www.garmin.com
http://www.magellangps.com/en/
those are the two sites i go to.
i guess it all depends on what and how you are going to use it. i use mine in conjunction with a map program i have, that way i can add waypoints onto the maps and print them out. i currently have the garmin etrex summit, comes with a lot of bells and whistles that i never use. also have the rhino combo gps and radio, again they come with a lot of stuff i never use. recently i started checking out the magellan line, have the sporTrak color, it is nice because i can download portions of maps to it, either topo or street maps. the one i use the most right now is the magellan eXplorist 300. it does not hook up to the puter and there is no way to update it, but i have found it to be very accurate. it is a simple unit, not a lot of useless stuff in it, easy to setup, carry, etc. Magellan just came out with three more units, explorist 400, 500, and 600, you might want to check their site and see what would interest you. i guess it all comes down to different strokes for different folks.