Favorite expansion pack?

I picked Seasons, because the sense of time passing, the calendar, and the ... seasons have all increased my immersion considerably, and that's important to me!

Get Together is probably my second choice, because clubs are really flexible, and I like using them to herd the background sims ... I like creating clubs my main sims DON'T join more than I probably should. But it makes the community lots more interesting when I, say, go to a pool and the local swim club is there, or whatever.