What are the best Sims 3 expansion packs?

Which expansions you'll enjoy most depends on what sort of thing you want to add to your game!

Everyone likes different aspects of the game, so you could take a look at some expansion guides to see more of the features of each expansion before you make your choice.

This page has a brief overview of the main expansions: http://www.carls-sims-3-guide.com/expansionlist.ph... and you can click the titles to go to a much more detailed guide for each one.

Personally I'd rank them from best to worst like this:

Late Night

Ambitions

Generations

Showtime

Pets

World Adventures

But that's just my opinion! The link I gave you to the expansion guides will probably be your best help in deciding what to get :)