My wife got me a nuvi for christmas. Think it was normally around $200 but was on sale for $80. Either way you can't really go wrong for $80. It doesn't have as many crazy features, but all I need it to do is tell me how to get where I'm going. I bought a handlebar mount for it on ebay for $1.50 shipped and I'm good to go. All I've gotta do now is make a cable for it so I can use it for more than 4 hour at a time off of the battery.
The only thing I haven't figured out yet is if there's a way go to onto mapquest or somewhere like that, and plot out an actual route I'd like to take, and send that to the GPS.