I'm using a Etrex Vista C (old, but still works great). I also have a Samsung Moment (Android). I like c:geo, but if you're out of cell range you're hosed. I've started using Geobeagle and just upload my PQs to bcaching.com and then sync with Geobeagle. That way I can still use it without cell service once it's synced.
I typically use my Etrex though, and just use the Moment to read the details. Let's me go paperless with a lesser GPSr. My lovely girlfriend, uses her EVO 4G. That GPS is pin-point accurate, it's sick.