I used to drive for a living and I always used maps, despite a sat-nav unit being available to me. If you spend some time studying a map, you've a mental picture of where you want to go, rather than just blindly going along. Should something unexpected occur, you can improvise. You can also get a feel for the route (will you be going through hills, etc) and it might be that your journey takes you near something interesting; with a map, you can see this and make a detour, with sat-nav, you'd miss it.
Secondly, (the social/dehumanising aspect) map reading's a (dying) skill in itself; I think people rely on computers too much and they'll mess us up in the end. What ya gonna do if you're stuck in the middle of no-where with a broken GPS system and no phone signal?
Thirdly, they're not always accurate. I say I used to drive; one of my colleagues who wasn't very good at map reading bought a GPS system-it got him lost on more than one occasion, including sending down 1-way roads and...round a (albeit big) roundabout the wrong way!!
They're good in unfamiliar cities.
