Never been attacked by trolls which is the only thing I'd be worried about, as they could destroy my base. Had dwarves and skeletons in Meadows/Black Forest, but never been attacked in the Swamp or Plains where I usually just keep a farming base for plains-only crops.

I tend to build against the water for a side I don't have to guard and also to launch boats, and cover the other three approaches with palisades and put a walkway along their top so I can bow-snipe attackers.

The wooden trap things seem to be destroyed easy so I don't bother with them, and I don't bother with pits or raised terrain, because it is easy to just repair walls as they are being damaged. I often farm copper in the Black Forest by putting a palisade all around it; mobs tend to walk around it, and if they do attack a wall, it is easy to just repair it and then continue mining.