What packs are your must haves?

Island Living and Snowy Escape
The Sims at its core is about going to work and getting promoted, but what for? They need to have something to make the drudge worthwile, therefore the vacation packs are essentials for me. I'm not a family player by a long shot, but my sims do have families and seeing them together is always nice. I also enjoy sports competitions, and these packs offer many opportunities to hold one.
Snowy Escape also brings tents, making Outdoor Retreat obsolete as a must-have pack. I'd still recommend it if you enjoy off-grid or rags to riches gameplay.
The science sets from Strangerville go well with IL's conservationist career. Another plus for IL: this career also allows for changing the rules of the world via global policies, in a less silly and less buggy fashion than Eco did.

Cool Kitchen
Ice cream is not only fun, it is also a reliable way to slim down sims in rotational play if you do not want to use mods.

Get Together
I love the world with its three different, very distinct districts, and the premades.
The club system can help with skilling and career advancement, but also to breath life in venues and costumize your world. Or just for roleplaying. Or simply to quickly summon a number of sims to your lot. The possibilities to use and exploit this pack are numerous.

Discover University
No way around this if you want to use cc vehicles from motor bikes to quads (especially if you also have JA) to functioning wheelchairs and horses (not kidding you). If you are not interested in that kind of thing feel free to skip. I played "fake" universities before this pack and never felt I needed it. Alternately the bike mesh from Eco Lifestyle might work as a base?

One of Get to Work and Dine Out
For restaurants or bakeries (although your "bakery" can also sell pizza or anything, really. The only downside is that townies won't eat on site). Probably not essential, but recommended.
Luxury Party's buffet and punch bowl fountain go well with either of these packs. I slept on this pack for long, but got a lot of mileage out of it when I eventually got it.

Get Together - I thought the club dynamic was fun and really helped me bring sims together to do activities as a group. The obvious ones like Dance clubs were super cool but you could also create clubs for mundane things like one Mansion owner I had ran a club called the Cleaning Staff and he'd start the event and they'd show up and start doing household chores. Works better than the butler. Another one was the Blood Bath club which was Vampires showing up at a Venue and their club activities involved drinking plasma and using vampire powers. It creates a pretty crazy atmosphere. I always mention that Windenberg is a wonderful town.

Island Living - It's just a beautiful place and it has a nice open feel. I think they caught the island living vibe pretty well and I really really love the mermaids. So yeah, my idea of fun is watching Sims fishing, swimming, and tanning.

Vampires - Vampires is the most complete Vampire experience I've ever seen released. 3 very different aspirations, a huge tree of powers and weaknesses that let you create different themed vampires, it included a massive victorian theme, and Forgotten Hollow is a genuinely well done. Whoever made this pack knocked it out of the park.

For me I like packs that add something totally new to the game that isn't already there so these are my must haves that I recommend most:

Island Living - Totally different to everything else in the game and it adds a layer of fun and it's the most "open" feeling out of all the worlds.

Jungle Adventure - One of the best build/buys, again totally different to anything else in the game and it brings a lot to do.

Realm of Magic - My favorite life state, I love Glimmerbrook and the whole vibe of it. However the best part is that you can use your powers to go around setting things and other sims on fire. You were happy sleeping in that bed? Not anymore! Fire!

Dine Out - I enjoyed running a restaurant a lot. I spent like 6 weeks solid playing with this pack as there's just so much you can do. Run a disaster restaurant where everything goes wrong, run a nice restaurant and build it up to five stars, micro manage staff, etc. Or if you want drama you can open a restaurant that only sells poisonous low quality pufferfish ngiri, and watch the customers drop like flies! Then when you've done that you can always visit a restaurant whenever you want (just avoid the pufferfish ;) )

Spa Day - I was surprised how much I liked this pack. The stuff is nice, I enjoy the yoga and meditation and I always place a ton of spas. Plus it adds new bath options which you can use all the time to destress your sims.

Tiny Living - The only stuff pack worth buying imo, love all the stuff that comes with it, the murphy bed is very useful and I like the added challenge of building small homes and working with the restrictions.

As a whole I think game packs are the best pack type, they have a lot of variety and very useful things that change up the game.

@EnkiSchmidt so if I were to pick one pack - Snowy Escape or Island Living - which one would you suggest? (And others could share their input too!)

Hard to say they are both great packs, if I must chose one over the other I would chooose.....Snowy Escape since it comes with more interaction and more traits

Game packs: vampires and realm of magic but that's due to my personal gameplay style. I like occults a lot and S4 did a great job with them.
Expansions: seasons because of the huge world overhaul. S4 is a different games with seasons. I wouldnt say that it is the best thought out pack but it is still the most basic. Get together: the club feature is an absolute game changer with many game and storytelling uses. Eco lifestyle: a bit niche but overall one of the best expansions. Very fun and rewarding gameplay.
I think it all has to do with your playstyle. If you like open ended rotational gameplay then go for get together or eco lifestyle. If you lkle set solo style gameplay then go for snowy escape discover university or get famous.

"permanentrose;c-17756131" wrote:
@EnkiSchmidt so if I were to pick one pack - Snowy Escape or Island Living - which one would you suggest? (And others could share their input too!)

In my opinion Island Living is easily better. The majority of Snowy Escape you can already do with Seasons (you can find tons of Japanese builds without the pack, just place them in an existing world, make them rentals and send your sims there for winter vacations). Whereas with Island Living there isn't a single other world like Sulani, it's the only world with functional beaches, the only world where you can build houses over the water, the only "tropical" world, you can go diving, use jet skis, sunbathe, visit the island festivals, etc. It's a gorgeous world to play in and it's very much an essential pack and a gamechanger in my eyes.

I second Island Living. Personally I do not have Seasons, so doubling on winter content isn't a problem. But the only thing Snowy does better than Island is making skills matter. All IL activities require is a little Fitness and you're set, Snowy to the contrary has a skill for each new activity.

Cleaning up Mua Pel'am is fun, the conservationist career really makes a difference in gameplay, whereas Snowy's office drone career only makes sense in dysotopic/challenge saves. IL's festivals are way more fun than Snowy's, they may be smaller, but feel more alive, they really fit the island community setting. On a more deviant note, volcanic eruptions are amazing (albeit save, lava bombs won't ever strike objects, although I had a case of one igniting something close to it). I cheat the environment to "industrial" after an eruption (requires Eco) for extra visual impact.

Thanks @EnkiSchmidt and @Onverser! I do have seasons, so my sims get to experience the snow, and I don't think I have a burning desire for more winter activities. Ice skating and playing in the snow with Seasons is enough for me.

So I currently own Seasons, Cats and Dogs, Get Together, Get to Work, and City Living. I have no desire for Get Famous or Eco Living based on things I've heard about them. If I do get another expansion pack, I will for sure be torn between Island Living and Discover University - VERY different experiences haha.

Mermaids honestly don't thrill me though, which is one pitfall to Island Living. I don't really want to have occult sims in my game. I have one token alien family in my game, but I never actually play them, and one male sim who currently has an alien toddler via abduction, but honestly that storyline bores me too. I think I might be in the minority when I say I really don't want more magical/supernatural/occult play in my game - at least I save some money because I will probably never get Realm of Magic, Journey to Batuu, or Vampires haha.

Also am I the only one is is totally into stuff packs? Sometimes I just love getting smaller stuff to enhance my game rather than an entire new world (though I would like more lots, just not always a whole new world haha) or some radical game play feature. Like I cannot imagine having Get Famous or Eco Living since they seem like they change the entire structure of your game with a lot of their features. Seasons so far is the only pack I own that has so radically changed my game that I almost felt like I was playing an entirely new game when I started a save in the dead of winter haha.

My favorite stuff packs are:

Tiny Living - I feel like it has a lot of nice build mode items and the tiny home challenge is just perfect kind of extra content that's not too overwhelming that I like adding to my game

Toddler Stuff - Ok, I will admit that you can get just as nice clothes and hair from CC creators, but I did start using this pack before I used CC. I just really like making cute toddlers, and I remember how limited they were in TS3 so having so many more options to make unique toddlers is totally something that appeals to me. And the toddler playdate is a nice feature.

Laundry Day - Yes, I'm annoyed that it had to be it's own stuff pack instead of included in a bigger pack, but I like the realism that doing laundry adds to your game but even more than that, I LOVE LOVE LOVE the build mode and CAS stuff from this pack. I use them all the time.

I also own Romantic Garden and Bowling Night, which aren't that remarkable but I don't regret getting them. I plan to buy Nifty Knitting eventually, and a handful of other packs seem like a lot of fun too, just try to pick the best ones when they go on sale :)