On the subject of maps, I try to take ones of a scale that suits the terrain- if there's lots of bits near buildings/built up areas, 1:25,000 ('explorer'- yellow, I think) are best, for most mountain/woodland areas where the terrain is more vast, 1:50,000 ('landranger' - pink) is my favourite. Don't bother with any sort of map other than OS (any other sort of map is a toy once you've used OS). Also, don't get laminates- just use pencil on them and keep them in a map case. They're cheaper and easier to fold.
Maps are also a great safety tool- give mountain rescue a 6 figure grid reference on an OS map and you're laughing.
Buy 'em here, my local Ramblers Association swear by them

:
http://www.themapshop.co.uk/Landranger.htm
Top Compass Tip: Take bearings of stationary objects- not things like another party of hikers in the distance or sheep as I have seen some people doing
Wyrdness: I know what you mean about people like your ex. I see people in the mountains with no rucsac, wearing shorts and a t-shirt, a flash GPS (with no map

) and a pair of fashionable, but not at all suited to a real mountainside 'hiking' boots. The outdoorsman equivalent of shorts and t-shirt on a GSX-R 1000
One more things re: hiking- do some smaller practice ones first before embarking on overnight ones, even if you're in good shape. I don't know for sure what the sports science of the matter is, but hiking seems different to other activites- I've seen some otherwise fit people really struggling after climbing a large hill and I've seen some porkers powering along for hours. I'm pretty sure it's something to do with how strong your quads (thighs) are as that seems to be the thing that hurts most, usually when you're making a steep ascent.