I don't want to start a war between paper and digital maps. So let's say one have to find a good digital maps and software for modern phone.
Open Cycle Map seems to be very good. It's free, pretty accurate at least in some parts of world.
In Android phones you could use Androzic with Ozimapper. You get maps easily from online and can manually save and transform them to offline maps. However this Androzic doesn't have an ability to save online maps to automatically to ffline whenever looking at some map area online.
How about iPhone? Are there good free map apps, which could use online Open Cycle Maps?
Are those programs capable for automatic offline maps saving? (the feature which is missing in Androzic))
For those who OCM is unknown: Open Cycle Maps is basically openstreetmap version dedicated to cyclists. There are some special icons like bicycling shops and cycling routes marked.
And please don't start discussion about best GPS receivers... to keep it simple. I do have GPS, mut it's obsolete because phones have gps today. I have used OSM in GPS, but OCM is very difficult to find and create to Garmin.