I think we've got 3 candidates:

1. The Daft Punks: total surprise and mindblowing set. Introduced the robot suits.
2. The Chemical Brother: amazing visuals though perhaps a bit dated
3. Skrillex: opened everyones eyes to the future of EDM. A set so intense it knocked the wind out of many in the crowd.
4. Sweetish House Mafia: anticipation for this may rival any act in Coachella history, but we will have to wait until April to see if it is founded.

Serious replies only.