Eccentricities:
1) Tombs/coffins are setup in either one of two ways:
a. At the bottommost z-level, in the Halls of Silence, or
b. In the legendary dining room.
Crafts forts tend towards a), Sparta forts tend towrads b). Regardless, every dead dwarf gets a (N)ote about their cause of death or anything else of interest I remember about them.
2) Rank and file dwarves get the exact same room type -- all furniture made of the same stone, with the exact same layout. It's very hotel-ish. Legendary dwarves or nobles get individualized rooms. I will often theme them based on a material the dwarf likes.
3) Any member of my military's goal is to become legendary with all weapons -- wrestler, hammer, mace, axe, sword, spear, crossbow, in that order. Thus, for fighting off ambushes, I am often sending champions who are legendary with their axe out with swords, which they are dabbling at. Soldiers who suffer nervous injuries are relieved from duty if they are below elite, or switched to marksdwarf immediately.
4) I love making plumbing, but I hate deconstructing walls. So I install doors *everywhere*, even into things like pressurized magma pipes. This has caused more than one curious child to die, as I tend to also not remember to lock the doors.
5) I never use artifacts to bump up a noble's room value -- they always go into a vault or a museum.
6) Traps are for catching wildlife. Ambushes and sieges are handled by military. I will sometimes make an exception and have a single line of cage traps set up in an entranceway so I'm not bothered by snatchers; in this case, I will often set up death mazes full of traps to deal with the captives.
7) Large rooms tend to be setup in some multiple of 10, plus one -- the size of designating a tile, and then shift-arrow'ing in some direction.
I very, very, very rarely dump things. Even if I've got 3000 diorite lying around, I will setup craftsdwarves to pump out trade goods rather than dump it. I *will* offer things (as in, give them for free) to caravans in preference to dumping them.