Gtoast:

I use a Garmin GPSMAP 276C right now on my duc. It's great! based on Long Distance riders on the BMW touring and adventure list (and my own experience), it's perhaps the best GPS unit on the market for MC applications. Also good for handheld use.

1. fast processor (to update the map in real time).
2. currently the largest color screen with the highest resolution (was the most important issue for me - to be able to see all the info while riding).
3. intuitive controls/layout/information that can be customized.
4. voice commands!
5. lithium ion power for about 6-8 hours per battery (has 12V wiring capability too) and prevents problems with vibrations.
6. expandable memory to 256MB (to save detailed map data), though uses Garmin proprietary memory instead of CF or SD memory.
7. water resistant.
8. downside is that garmin's mapping software for the PC (to upload/download waypoints, routes, tracks, etc...) is a bit hard to use.

The 276C only comes with a basemap (very basic map) of the US. You need to buy specific map details/areas or the entire US, Eurpoe, etc., separately, which can be costly, to autoroute (be able to create a route on the PC, upload to the GPS unit, and have the GPS unit give turn by turn directions).

Here's a pic on my bike:



HOWEVER, based on the factors listed in your original post, you may want to look at the Garmin 60C/60CS. It is more designed for hiking & in cars. It doesn't have expandable memory (for those long trips) but has a great color screen (same technology as the 276C but smaller size) and comes with the detailed GPS maps. I don't think it has voiceprompts which you really need for car applications. Check out garmin.com