Help picking a GPS

[watcher]

I'm posting here because I'm fairly sure that someone of you hunters use handheld GPS units.

I want one to do a 'sort of' survey of my property. The property has been professionally surveyed so I'm not trying to find the boundary markers. I'm wanting to draw a fairly accurate map overlay so I can plan where to build our 'real' house. One thing I really need is accurate altitude measurements to find the highest spot because of flooding concerns. The higher the starting spot the less dirt I have to PAY to have hauled in.

A used unit would be fine if it would do the job. AAMOF, a used unit would be more what I want because of the price

Anyone out there have a model in mind that would fit my needs or would any unit less than X number of years old work or whatever?