I have the Magellan Gold (I'm pretty sure that's what it's called), I bought it specifically because it's a little smaller than some of the others, makes it easy to mount on a bike. Especially if you have tubular bars. I got the RAM mounting kit from RKA, it's one of the best peices of equipment I have ever bought.
And I agree with Gambler, sometimes it IS fun getting lost but you can just shut off the GPS if you don't want to know where you're going! I've found that there are alot of roads that you see going off a main road and you don't try them because you'd at least like to have some idea of where the road ends up. With the GPS, you just move the cursor arrow along the road you're thinking about and voila, you can see where it will take you! I highly recommend them, I've tried more roads that I probably wouldn't have tried otherwise because of the GPS.