Cats & Dogs, Vampires or Parenthood?

Parenthood IMO pretty much requires you to play your kids and teens longer if you want to benefit from it... so you have to keep that in mind (I would never have managed to get them any of the traits or the aspirations done on normal lifespan). So get it if you like spending time playing those lifestages (it makes teens a bit more interesting but still boring overall). I can't say I've seen much difference when the kids or teens get in a phase though... If you care more about playing adults and like going through kids and teens as fast as possible, don't bother.

Cats and dogs - you'll have to spend a lot of your Sims time taking care of them. My Sims very rarely interact with their pets unless I tell them to, and obviously it's time you won't spend building skills or whatnot. Sometimes it just feels like less work when you don't have pets in your household (plus the whims are VERY annoying and mostly useless, so get the pack if you don't mind having 'buy more balls' or 'take your dog for a walk so you can waste 3 Sim hours for 10 aspiration points' whims showing up constantly). I love pets in RL but honestly not sure how I feel about this pack. It just could have been done so much better.

Vampires - I'm not very interested in that theme so haven't bought it yet, as it's something you can't really ignore once it's installed (I'm already annoyed to see aliens everywhere).

I guess between the 3 I'd get Parenthood...