We're pretty full blown. Miniatures usually on bases, dwarven forge stuff, generic wood toy blocks, some trees and foliage, some rock terrain. We use small cardboard counters to number the foes like F1, F2, etc and M1, M2, etc. I recently picked up some Gale Force Nine stuff like death markers (little white skulls or body outlines), fire walls, smoke clouds. I have some templates for radius and range (balls and cones).
I used to have an entire tavern/bar fully painted (by a damn good competition painter) that went missing during a move
. I've rebuilt up all the parts I lost and added parts to make it an inn also, but have yet to do anything about painting them. I'm debating buying a building online for it (which are kinda small for my taste) or building my own using foam and balsa wood. It's rare we have a dedicated diorama like that, but an Inn/Tavern is so commonly use it's worth it in this case.