Verified answer

Sims 2 Seasons, or you could wait another month for Sims 2 Apartment life to come out.

Sims 2 Nightlife!

Sim2 double delux will get you further for less money but not if you have either the base game or nightlife it won't. Read the case and decide if its worth it first. If you don't have nightlife that would be my recomendation and I love the pets expansion. It only gives you pets though and some people are disappointed to find there isn't much more stuff.