I use an Oregon 300, now discontinued but there are newer versions; with OS 50K map added option (you can buy this at a later date).

I think its a great unit but find sometimes the screen suffers in strong sun light. It's great for paperless geocaching and you can write short logs while out, good for when you do loads of caching in a day. Easy to download and upload from the unit and can hold 2000 geocaches plus waypoints.

Best thing is to go to an Event and see different units cachers have with them and ask what they like and dislike about their GPS.

Oregon 300 does the job for us, simple to use and pretty easy to upload and download info.

I know this is not that new of a thread, but thought I would contribute anyway.

I don't have any good advice on newer or top end equipment. I can only talk about what I use, which is real old, but reliable equipment, and good if you're on a very tight budget.

I use a Garmin eMap as my GPSr. It can fit just 500 waypoints, but that is more than enough for my occasional caching. The screen is monochrome, but of a good readable size. And as the name suggests it has map capabilities. This cost me £50 second hand a couple of years ago, and came with a memory card installed with basic maps of the south of the UK and a car power lead. It takes two AA batteries, which I have a couple of sets of.

If I am going out to do more than just one or two caches, which is not that often at the moment, I load a html formatted PQ using GSAK to my now quite dated K800i phone so I don't need paper print outs.