I have a good bit of experience with both the 60CX and the 60CSX as our search and rescue team uses them along with the Astro for the dogs and they are also the "standard" GPS for FEMA. One thing we do is upload our data files into a mapsource as the active log and save that file before doing anything with it because Garmin strips a lot of info off of a file when you save it as a saved track. Mapsource makes it easy to Clip the data files later. actually mapsource is a good little data manager but not much in the way of mapping. We save all files on computer and clear the GPS out after each use.

That said - not of lot of info on biking uses from me, but you may want to check out Topofusion which is a slick and cheap mapping program developed by some mountain bikers and constantly being improved. You can try it for free with a fully functining demo program (which just obliterates some of the tiles. A lot of functionaity there and you can overlay jpeg files like park maps, GIS maps, etc right into the program.

We use Maptech Terrain Navigator Pro for all of our purposes but it is a bit expensive for personal use.