I use reveal to get a feel for where the caves/magma/adamantine is, but after that I just drill into whatever mountainside looks the most easily defensible. Usually a ditch with a drawbridge is enough to keep pests out, with guards later on to watch for ambushes. After I establish a farm(pop a lake), build up a small supply of wood for beds, I seal myself in and use loose modular design. I put bedrooms in a easily expanded butt end of my fort, with enough hallway to keep noise out (sometimes filled with dining rooms or barracks or offices, etc.), then build production areas in clusters around a central shaft. if you were to view it from the side it would look something like this, almost every time;
_|=+DOB
#|F+==B
#|C+==B
#|M+==B
#|#+##
" + "
A/M+##
Where += central shaft, D=dining, O=office, B=Bedrooms, F=Farms+farm related shops/storage, C=Craft shops(mason, etc)+storage, M=metal production+storage, A/M= adamantine/magma. Most those areas kind of wrap around the shaft. I usually just throw in a crypt somewhere whenever my first episode of Fun occurs, and military stuff gets stuffed in near the farms most often. I like to put the well/hospital off to the side, wherever it's easiest to route a brook underneath and I don't use any serious plumbing beyond that. The dorfs have legs, I say they can use 'em. Most of them don't have much to do anyway, I hardly ever have any problems, and it doesn't take much of a military to keep out ambushes/cave critters, especially when you can just shut your doors.