A very old edition of memory map, which I inherited, sadly without a key so I have not been able to upgrade. I have quite a lot of maps both 1:25k & !:50k. The distance measuring tool is most useful, always use tracks rather than routes and going into 3D view is very useful. My stock of OS paper maps are so tatty that I would rarely carry one, other than carefully wrapped in rucksack. But I always compile a map from piecing together screenshots from Streetmap, The large view is useful, because the scrolling tool in Pipick (screen capture software) produces large tiles to join together with photo editing software.
Somewhere along the way I taught myself to create files to put into my gps unit by building a series of map references together, I even could down load a route file but i just don't seem to have got around to that as the GPS only comes out to pinpoint my position. My route from a scan, printed out from a home printer then laminated seems to be the best option for me, as the maps can always be enlarge or reduced to show the detail I want for a particular route.
Google earth is a very useful adjunct to online mapping, Telltales such as tractor tracks leading to gates etc. can be particularly useful.
Since I am now getting past some of the longer walks in remote places and wish to reach special locations in inhabited countryside, aspect is an important consideration, the need to pass locations where the occupant might take exception to my presence, can be planned for using this available software.
I suppose I am similar to Ninthace and Sussamb, but without the GPS. Just an old dinosaur with a few bits of new techno' tacked on