Well, I know I'm going to be burned on a stake for this comment, but here goes:
I don't suggest buying Lego Star Wars 2.
Hang on, let me clarify.
The game is great, it's fun, it's cute.
That being said, my wife and I rented it over the weekend and beat the story, got 500 achievement points (on the 360) and were like 70-some % finished the game.
It would almost be a waste of money for me to rent it a second time.
A game needs to have replay value for me to buy it, and hey... It just doesn't have enough.
Sorry guys.