Which Stuff Packs do you think are worth buying?

I'd say all of them are worth except Luxury Party, Cool Kitchen and My First Pet, but it depends on what you're looking for. Imho Romantic Garden is only good for the CAS items and Fitness Stuff only for the Build Buy ones, so they might not be for you. About the other ones, I say catch em all, especially Movie Hangout, Laundry Day and Vintage Glamour.