I liked Katy Perry's and Metallica's (even though I'm not a huge fan of either) and Kendrick + Imagine Dragons absolutely murdered it.
Link to K Dot and Imagine Dragons: http://www.youtube.com/watch?feature=player_detailpage&v=eeAkgmq3I3g#t=11
Macklemore + Madonna and all those weddings were sooo bad though. Ugh. So heavy handed and contrived. And I was expecting so much more from Trent + Qotsa + Dave Grohl + Fleetwood Mac dude and the Daft Punk + Stevie Wonder + Pharrell performance was pretty lame too.
Now this will be a beautiful death. I'm jumping out the window, I'm letting everything go. http://i.imgur.com/6iJV1H9.jpg