Hi, I'm justfred and I'm a mapping addict. ("Hi, justfred!")
I have the Garmin GPSMap 96c - the aviation version of the 76c.
-I have it loaded with maps from the Garmin MapSource CitySelect (as well as the latest Jeppesen data).
-Nice big color screen, multi-mode so it's either in car/walk or plane mode (or boat mode which I don't use). Large enough to see well but small enough to still be handheld.
-Plenty of storage space for waypoints (geocaching) tho those get in the way of info on flight maps - I usually just delete all geocaches before flying.
-The car mount is designed for the dash, not the windshield.
-It's expensive but absolutely worth it for flying.
-I also have an eTrex Vista, that I sometimes use for geocaching instead; but I'm spoiled by the big screen in the 96c.
-My wife has a small driving-only StreetPilot i5 that I use more than she does; for the size it's got a pretty great database, tho it's useless for geocaching or off-roading.
-I've also use the eTrex connected to the Mac (iBook) running National Geographic Topo. Required a serial to USB converter, but otherwise worked quite well. But the Topo street maps are outdated, in some cases being over 10 years old (I15 through Escondido missing?).
-None of them "plays well" with Macintosh or Linux, yet, in that there's no Garmin software for loading maps, etc. Garmin has promised better Mac support, but I haven't seen it yet. But other manufacturers (Topo, for example) can read the output data. Wish these manufacturers would just default to open standard rather than trying to stay proprietary.