Island Paradise, University & ITF are my three fave expansions now. It used to be Generations until Seasons come out, then it just kept getting better. I am sorry to hear that they aren't making any more expansions with Sims 4 coming out, but am happy at the same time because now I can finally enjoy the game to the full extent!
I have not explored Island Paradise all that much yet, and I want to meet a mermaid and go deep sea diving, so I am looking forward to that. I love the layout of the island(s) and am looking forward to playing the expansion some more - as soon as my issue gets fixed