My advice would be to buy what you REALLY want in your game. Unless specified otherwise.
My original Sims 3 disk got ****ed up so I bought a new one that also had Pets. Pets is cute too btw, but I haven't really done much with them as of yet.
These are the expansion packs and stuff packs I have bought and my reasons for buying them:
Late Night: I really love celebrity status and being able to go to clubs and dance. Vampires are cool too.
Generations: Since I really enjoyed my teen years and stuff, I wanted to be able to have more fun with kids and teens, and everything else basically.
Showtime: I love music and I wanted to create Superstars and I'm my way to doing so
Katy Perry Sweet treats: I love katy's outfits so ultimately it's awesome to have them in The Sims 3.
I might have more money to spend for my birthday, so I might buy one more EP then:
I only have 2 EPs (Ambitions & Showtime), I desperately want Supernatural but My computer is super laggly with just 2 EPs so I'm waiting to get a new PC before I get anymore EPs.
I'm excited for University too
The pics look AMAZING!!
I only have the base game, Supernatural, Late Night, & Seasons. I wanna get Showtime, Pets, Ambitions & either Generations or World Adventures. I also want some stuff packs but that's a different story. Next paycheck I'll treat myself to some new ****.
It depends. If it buy it from Origin right now their having a sale for only the Direct downland you can get it for 20 bucks but If you're cheap like me, you can get a used game from Ebay or even craigslist for the same price or cheaper. I got mines for $10.50 + 3.95 shipping
Your house looks amazing. 
