Wow, I just skim read 7 pages and nobody has mentioned any OpenStreetMap based maps !
If you've got a Garmin device you can most likely put one of the OpenStreetMap based maps on it for free. There are a number of different style maps depending on your focus. Road (car), road bike/touring bike, MTB/walking
Being the wikipedia of maps it is not complete everywhere but you can add routes yourself. If it is on here it is already mapped:
http://www.openstreetmap.org
I have a Garmin Dakota 20. Typically, I will plan a route online with something like bikeroutetoaster and upload to the GPS then follow. If you need to deviate from that, the routing intelligence of the map becomes important so you don't end up on the nearest motorway.
I've used the OpenCycleMap version to cycle tour with the national cycle network highlighted like a motorway. OpenMtbMap for offroading then found the nearest fish and chip shop by browsing through the food menus on the Garmin. Velomap is done by the same chap as OpenMtbMap but has better routing for road and touring bikes.
It's not all perfect as its based on reverse engineering data and postcodes are copyright so they are not in OSM.
For more info:
http://wiki.openstre...Garmin/Download
They work on car based Garmins like the Nuvi if you want to try it the maps out.
Phil.