I recommend buying the packs in bundles or sales. You can buy EP + GP + SP bundles on Origin, or 1 GP + 2 SP bundles from third party resellers like CD Keys. Even if you don't care much for SPs, the Origin make-your-own-bundle slashes off 35% from the price, so you'll still get the EP and GP cheaper than if you had bought them without the SP.
That said, I do agree that you already got some of the best packs in the game. If you're into pets, you should get Cats and Dogs because the animals are adorable and the gameplay is pretty fun, even if it has a few shortcomings. For GPs, next to Parenthood, I like Dine Out and Jungle Adventure because I like taking my sims out to eat and JA has a bunch of fun new things to do. For SPs it really depends on what you like. Backyard Stuff is my favorite because of the CAS, but you might find the others more to your liking.
It really depends on your preferences. I'd say most of the EPs and GPs are pretty good. My least favorite is probably GTW because the gameplay is pretty bland, but it also comes with good CAS, so at least there's that. I still don't have Seasons (yet) and Vampires (not my thing), so I can't comment.