Probably Legoland or Rock Raiders is my favourite. Whether they're the best is disputable. They both benefit from a lot of nostalgia.
My personal worst is Lego The Hobbit.
It failed to add anything substantive over Lego Lord of the Rings, had fewer characters, funny items, levels and smaller world map. It was also much much buggier.
But the big kick in the teeth is that it was only 2/3rds of a game at full price, and there are currently no plans to release the final movie as an expansion or rereleased game.
Lego Star Wars: The Force Awakens is scary in the same way, in that there are 5 more movies coming out at least and I don't want to buy 5 Lego games for each, even if Lego TFA was one of the most fun recent Tt Lego games.