I have purchased a crazy number of handheld GPS units over the last 15 years (I use them at work and play), mostly Garmin units, but also Magellan and Delorme. Garmin units are my favorite, hands down.

I own a bunch of newer models, but surprisingly, the two units I use the most are the venerable GPSmap 60Cx and my Oregon 450 (even though I own a newer GPSmap 64s and Oregon 600). Those are my votes for great "classic" GPS units.

I'll also put in a pitch for the eTrex 20, if you are looking for something functional, durable, and inexpensive. (I own 6 eTrex 20s and 30s for work.)