I think that Get Together is probably one of the first packs you should buy. I think that pack is a lot of fun and it gives sims a better opportunity to make friends because of the clubs featured in the gameplay. It also encourages your sims to leave the house more often because just sticking to gameplay in your sim's house can get boring....
I also really enjoyed City Living. There are a lot of activities to participate in because of all the festivals that are featured in this EP. It also adds some new careers to choose from as well....
If you're an animal lover such as myself, I would recommend Cats and Dogs also. You can buy a vet clinic and play as a veterinarian. I think that having pets adds another element to gameplay as well.
