I have used Garmin's GPSIII+ and now use the GPSmap176c.
I really like the 176c. It has a large screen and I upgraded to a 64 mb card. On this is loaded MetroGuide for most of the southwestern USA, Worldmap from Mexico to Panama, Eastern Canada and Central Europe all the way to Nordkapp.
It is pricey but I am very happy. The other choice would be the GPS V, a smaller unit like the 3+ but not upgradable and only has 19mb of space available.
Hope this help.
Jay Kaminsky http://jkam.home.att.net