I have a Lowrance Globalmap 100, which I'm very happy with.
This model was one of the first GPS units with a built-in map, and is probably about 5 or 6 years old now. They make plenty of newer models, though. I also used to own it's predecessor (without the map), which was marketed back in the late 90's under the Eagle brand name.
These are great units. Not quite as prominent and "trendy" in the outdoor stores as Garmin, Magellin, etc - but their commercial models are very popular with sailors and pilots. The handheld models, although less commonly found in local stores, are ideal for in-vehicle and on-foot users (like me). I have it on good authority that these units have some of the best receive sensitivity and signal processing on the market. My one will usually get a fix in clear sky from totally "cold" in about 1-2 mins. If I then turn it off, hike for a while, and turn it back on again - I usually get the next fix in about 30 seconds. It's surprisingly good under tree cover too - in fact it used to give me a fix from INSIDE my old apartment (top floor, flat roof).
Here's a link to the iFinder, a current handheld model -
http://www.lowrance.com/Outdoor/Product ... plorer.asp
And here's a list of other Lowrance models and their specs -
http://www.lowrance.com/Support/gps.asp
You could also check out this previous thread on GPS units -
http://www.caves.org/phpBB2/viewtopic.p ... hlight=gps