What Stuff Pack Should I Buy?

I agree that you should check out the SimsVIP or Carl guides and reviews if you haven't already done so. Every player is different after all so what packs you prefer will really depend on your play style. I chose Laundry Day because it offers lots of great content and suits my family play style. However, I also love Vintage Glamour, Romantic Garden, Movie Hangout, Cool Kitchen, Kids Room, and Toddler stuff just as much.

You should be able to purchase multiple packs at once using the add to cart feature through the Sims online store unless this has changed? I remember doing this a while back during an Origin sale.