How are all the expansions and stuff packs after Generations, Mairmalade?
I read there was one that added witches and fairies. Is it true? I was planning on getting a bunch of the expansion and stuff packs eventually. I don't have any stuff packs yet, but I have every Sims 3 expansion up to Generations, when I sort of got into a Sims slump.
Yeah, Supernatural came out recently. It comes with a new world, a lot of new interactions, venue types, build/buy/CAS items, and of course new life forms. Aliens are brought back (you cannot create them, but you can mimic the look of one). Same with zombies. However, you can create vampires, witches, werewolves, fairies, and ghosts. All have unique attributes towards them. Vampires were introduced in Late Night, but with Supernatural there is additional game play. If you're into that kind of thing it's definitely worth the buy. If not -- don't bother wasting your money.
Other than Supernatural:
Pets -- nice premise. Doesn't add much game play other than...well...pets. There are some cool things, though. If you're playing an instrument pets will howl or meow along, your dog can actually fetch you a date if its hunting skill is high enough and you have Late Night installed, a lot of country themed CAS options, a lot of lifetime rewards were added as well. If you like the ranch/country lifestyle I'd pick it up. Or if you just want to be a pet.

There's a lot of great user-created worlds that can make your experience more enjoyable. The Create-a Pet tool is SUPER extensive. You could probably spend upwards to half an hour creating one pet. Not worth retail price.
Showtime -- basically a refurbished Late Night. Adds a new world, a bunch of new social options and careers, CAS/Build/Buy items, venues. Some cool items are the new karaoke machine, photo booth, driving range, pool table, mechanical bull, list goes on. You can also set your own career outfits now which is nice. The new careers are Singer, Acrobat, DJ, and Magician. It's really fun to put on shows~ You can create your own venue and then before your gig you can decorate your stage however you want. There's a lot of cool props and lighting to choose from.

Plus if you have a good amount of Sims in your world (or a small world with not many venues and a decent amount of Sims) you'll get a pretty good turnout. Genies and the magic lamp make a return in this expansion as well. If you want more of that celebrity lifestyle and think you would have fun with the new career types, definitely worth the buy. Doesn't add anywhere near the amount of content that Late Night did, but it's not bad.
Seasons is just a classic. You can't go wrong with buying it. Aside from how gorgeous each season is, they all bring new activities like soccer, roller arenas, snowboarding, making igloos, splashing in puddles, trick-or-treating, greeting cards, gift exchanges, making igloos, there's a couple new party types and general interactions (writing love letters, faking sick, online dating, etc) and of course for every season you can make a festival lot. On this festival lot it's basically like a carnival. There's face painting, eating contests, kissing booths, haunted houses for fall, you can slow dance on the dance floor, there's a tanning booth for summer (or any seasonal use), ice rink, horseshoes -- LOTS LOTS LOTS to do. Highly recommend this. Plus as usual there's a lot of added CAS/Build/Buy options.
University Life (most recent release). I've only had it for a day and I'm in love. Goes beautifully with Seasons. I'm not going to give anything away, but if you want to buy only one expansion in the near future -- buy this one.