I still use a Garmin eMap because it is still a "favorite" of mine. It's just an old grayscale unit but it has a larger screen than an eTrex and it's lot easier to see and use. You can get the GPS, a memory card, and lo-res topo maps for under $200 if you shop ebay. I don't know if it will run the hi-res maps. But, if money is an issue it's still a very good choice.

I'll also point out that you'll want a GPS that will take a memory card. Some of the eTrex units do not. You'll want that feature to make it easy to swap map sets. The eMap uses a proprietary "Garmin" card and they're not cheap. That's a pretty big minus.

I'm pretty sure that some of the DeLorme units are compatible with the National Geographic Topo software. That's a pretty big plus. And, I think you can use your own maps too. If I buy a newer unit I'd have to consider that in because you can download all the USGS Quad maps for free now.