Favorite expansion apart from seasons?

I think polls are fun! So I really want to answer, but so many are asking about a favourite, and I don't really think that way; all the expansions, and the other packs, add to the game, and I think i would miss a lot of things about them if they were not there, even if some of them seem more thought through than others.

One way to answer the question would be to say Get Together though, since I would really like it if more of the packs had features that were so useful and flexible and non-intrusive to gameplay as the Club System.