I've always liked Garmins over Magellans for ease of use. Unfortunately, they quit making the old 12XL that served me so well a few years ago - including a year-long vacation in Mesopotamia. The eTrex I replaced it with doesn't have NEAR the antenna and is continually losing sight of the sky. They're both pretty easy to use, though I have no idea whether the eTrex willtake a Google Earth download.

Go try a few different brands out at the store, though. See which ones will meet your selection criteria (Google Earth download) and are the easiest to use. Next, make sure you have a topo map and good lensatic compass as backup - and carry extra batteries.