I'll just add my voice to the Garmin 705 recommendation. I haven't own mine too long to say to much about it but so far it seems to do everything I wanted it to do. I picked mine up on ebay and got lucky...<$200. JerseyJim mentioned that the map on the 705 was hard to read while riding. I should add that you can Zoom in and out with the map to view a larger/smaller area but the screens are small ( 35mm x 40mm ) but that pretty much goes with the territory of handlebar mounted bike stuff.
The big selling points of the Garmin 705 is it's ability to give you audible and visual prompts when you approach your planned turns ( for downloaded routes ). That and the fact that it also is supposed to run for 13hrs on one charge ( although I haven't tested that yet. ) The only down side I'm seeing so far is that there is a learning curve to learning all the functions. I can't wait for the weather to get warmer so I can really get used to playing with this new toy. So far I have only had the chance to test it once ( locally ) and the 705 warned me well before my turns as well as "at" the actual turn. So far I like what I'm seeing. Having a good GPS unit is really going to add a large degree of comfort when riding long rides in unknown territory.