I have the Garmin eTrex. The plain yellow one. No fancy graphics, no color screen, it just gives you the coordinates and other vitals. Love it. It's accurate, quick, watertight, doesn't kill batteries fast, and very lightweight. Plus it's very cheap, one of the reasons why it doesn't quite matter if it gets busted. I think I paid $70 for it while it was on sale at target a couple years ago.
I have some of my favorite dive sites, campsites along the appalachian trail, the keys, it can store quite a bit on it. My only complaint is that it limits the characters you can use to name each site. So you have to resort to abbreviations a lot. It has accompanied throughout many adventures and will continue to do so for quite some time.
If you want the graphics and maps: my buddy has the Garmin 76Cx. Which is also very good, a bit bigger, I'm guessing it kills batteries a little faster also. But very nice, accurate, and the compass works without having to track. What they don't tell you is: you have to buy the maps separately- according to region- to download them onto the memory card. Those are pretty expensive.
Since I prefer printed maps on waterproof paper (so I can take notes) I like the simpler one, but that's also mostly because I need to have the ability to use a real compass just in case of gps failure. That's mostly because I like spending a couple weeks in the woods every once in awhile. heh. Also the gps won't work to well in forests.