I selected Cats & Dogs, but it's probably a bit of a tie, to be honest.
Cats and Dogs for the new world (I LOVE LOVE LOVE Brindleton Bay and play it primarily) and the... well, the cats and dogs O.o
Get together for the new world (I LOVE LOVE Windenberg and play it secondarily) and the club system.
A close second is City Living because I love the CAS and build items, and the street food stalls (I love food. I'm a foodie). The only thing really stopping it from being my favourite is not being allowed to create your own apartments in San Myshuno or other worlds. I used to love that aspect of apartment living in the previous sims games (my favourite for apartments was Sims 2)
Last is Get to Work, but I don't hate it by any means. I've been lucky (touch wood!) in that I haven't had a particularly buggy experience with the careers in it, and I love the detective and science careers especially. I do think the retail system isn't as good as previous sims games, but I recently made a massive department store and am getting back into it.
