I've bought a used Garmin 60CSx a couple years ago and it has been bullet proof. Always comes home covered in a thick layer of dust. Probably taken quite a bit of shock, though it's been mounted on a Ram ball/arm setup. I use it mainly offroad one my WR250R and on my ATV, so it's been run through the wringer. I have also used it in my truck, but not as often. There are a bunch of states for which you can get free topo maps. Also Garmin ones. The best part of the 60CSx currently is they are going for way less than 1/2 of their previous price (a friend bought one last month for $169 and I've seen them below $150 on those "one day only" sales). Garmin came out with it's replacement, the 62 series, so the 60 series will be discounted until they are gone. While there are some fun new features and upgrades to that system, you can't go wrong with picking up a 60CSx for the current going rate. I chose this type of GPS over the larger Zumo type so I can use it for hiking, fishing, etc. If it will never leave your bike, then it's worth looking into the larger-screen dedicated units.
