i would be the first to promote buying paper maps, all of them, for everywhere, and enjoying planning adventures new over a cup of tea
i'd also be the first to promote not being wholly reliant on anything that runs off batteries for your single source of navigational knowledge
there are all sorts of types of paper maps currently available, both in terms of scale and intended user, and there are probably even more GPS based devices available for those that are inclined to either navigate with them or use them for confirmation or emergency purposes
horses for courses as it were
www.grough.co.uk "the inside view of the outdoor world" have launched Grough Route - subscription based access to maps of the UK. The varying subscriptions also entitle the user to a wide variety of add-ons such as aerial mapping, importing to GPS, printing route cards, and of course mapping routes.
Grough are in the process of creating traces for key events like the Fellsman, and are also keen to receive end user advice to develop the software.
The gold plated subscription is £57 per year for 1:25, 1:50 and 1:250 thousand mapping and the full gamut of options. That's about the cost of 6 paper maps.
Back to my first point, all of the UK in all three mapping scales would cost more than £57, so buy the ones with the strangest squiggliest lines and features on them, and subscribe to Grough Route for the rest.