most places seem to offer ceramic for sit-down customers? I mean, maybe not starbucks; most Starbucks I've been in don't really seem to have much of a sit-down area, so "for here or to go" isn't really a question. But most nicer places have them; it seems to go with having seating.

I personally have a strong preference for ceramic (not enough to carry my own, but when I'm going to be in a place, I ask for a ceramic cup, simply because it is a more pleasurable experience than a to go cup)