After looking over a few different GPS units made for bikes I decided to do my own thing. I found the Nuvi 200 for $249 at Staples. The unit is super conpact like only 3/4" thick and the best thing it has its own battery pack that charges off of 12volt.
I simply installed the unit with a high quality Velcro strip. When I leave the bike I just pull it oof and stick it in my poscket or the trunk. It runs 4-5 hours on a charge.
I'm planning an easy installation of a 12V gig-lighter plug under the seat. This way I can just have it charge when in storage.
The images provided were shot in the sunlight - I really like the MPH display since we got screwed over on our speedometer which you can barely read the mph in red.
By the way, I thought there was a thread that showed a GPS mount what fit on the brake cover - anyone have the link and does it fit the Garmin?