Well, I bought the "Ruins of the Wild" set for woodland/wilderness encounters, mostly to have some random trees on either side of the path. I've ordered the village set for some building interiors, but it hasn't arrived yet. I'm very sceptical that any set can let you detail a dungeon in play, so I'm sticking to dry-erase maps for that.
Edit: The WotC sets would be much more useful if they were laminated so I could use a dry erase marker on them.
Edit: The WotC sets would be much more useful if they were laminated so I could use a dry erase marker on them.