The choreography when killing Smaug in the Hobbit is unrivaled, but it's also wonderful to step into some Hobbit Arkenstone modes: I love the final Eagles flight of "Into the Fire" and the 3rd stage in the Cathedral of "Battle of Five Armies". Great graphics and wonderful soundtrack after hard action.
The final shot to finish the "Self Destruct" mode of the Alien pin is also very satisfying.