Wilderness, huh? How about "backcountry". There's a HUGE difference between those two terms, and that difference is your riding areas.
There's thousands of GPS receivers out there, each with their own pros and cons. Make a list of what you want, then go shopping with that list. Street maps? Topo maps? Tracks? Voice-prompted navigation? Battery-operated? Display size? Price? Removable/upgradeable memory? Serial output? Mounting options? Durability? Waterproof?
Is it something you're _only_ using on the motorcycle, or would you want to take it with you for road trips in the car too? Or on a snowmobile/watercraft?
Personally I ride with a 60CSx. If I had to buy a new one, I'd get teh 76Cx. Handheld, compatible with both topo and CityNavigator maps, has turn-by-turn directions but no voice prompts (just loud squawks), and can be powered from the bike/sled/truck but fall back on internal 2xAA batteries if external power is lost.
It's pretty tough, but I've damaged it a few times... one of the reasons I'd go with the 76 vs. the 60 is the different form factor without an antenna to break off, and the RAM-mount for the 76 wraps around the entire unit giving it more protection. The [S]ensor package is worthless; nothing more than consumer fluff to mark up the price.
Almost anything will have some level of Mac
compatibility. My 60 (as well as a 76) talks to my Mac without a problem. Garmin has tools for loading maps and managing tracks/routes/waypoints (BaseCamp, MapManager). There's 3rd-party apps that work well too, I use LoadMyTracks to move data to/from the Mac and Google Earth to lay that data onto a map. A little more work than using BaseCamp, but to me the benefits to that software outweighs the convienence basecamp offers.
LoadMyTracks can communicate with most popular GPS models via USB and serial connections. Google Maps has a GPS import utility. My 60 can also log tracks to the data card, remove the memory card and put it in a card reader to copy tracks to the computer if you want to do things the hard way.
First you need to decide features you want, then narrow it down from there.