If you ask five different people, you'll probably get five different answers. Really, it depends on your style of play, and what you enjoy. For instance, if you like that slightly ridiculous element of Sims, you might want Supernatural. If you're a family player, you might want Generations. If you're a pet person, you might want Pets. We can't really give advice - assume we all said "go out and buy World Adventures", you might do so and realize that it was a big mistake and that you don't really like it.