Garmin eTrex 30
Garmin Oregon 450
Garmin Dakota 20
I would add to this roster the GarminGPSMap 64s or 62s.
All of the above models are fine models to buy but I like the size and push button reliable characteristics of 60 series. I feel that the buttons are more resilient to the rigors of the outdoors.
To read more about buying a GPS:
Buying a GPS Receiver
Buying a Used GPS Receiver