I played it when it was released. I still load it up from time to time, usually to check on the details of a feature if I'm discussing it. I'll have a little play for memories sake.
It's hard to pick a favourite. Hot Date added so much at it's time of release, because I believe it was the first time we had community lots to visit! Restaurants were a favourite feature, but I loved building shops as well. Makin' Magic was brilliant, and I loved combining it with items from Unleashed, which had some great worn-looking assets. I liked collecting all the interesting ingredients in MM, and crafting spells and crystals. I particularly liked the old-fashioned features like the spinning wheel, baking with ingredients like flour, the nectar making, and the butter churn.
Superstar was definitely a favourite! I'd really like a similar theme for TS4 with active fashion, film and singer careers. The only issue I had with it was that your performance was based on chance, especially at higher levels. I'm a bit of a controlling player, so I prefer a more predictable outcome based on skill and effort.
I loved the vacation expansion, I liked that it gave us three new destination types to explore: snowy, outdoorsy, and beach. We have Outdoor Retreat for TS4 and I'd really like to see a ski resort and a tropical island at some point.
My least favourite was Livin' Large, it had some nice features, but it was a bit too OTT and I didn't tend to use the features that much.