Based on pure speed I would say the Olympic style sprint kayaks would be the fastest. I've seen them take down 8 men crew boats in head to heads. In surf an Epic would do. In whitewater it would be a downriver Wildwater boat. For gates it would be a slalom kayak. Depends which environment you are paddling in to determine the fasted craft.
I love to dance, but who needs the music- It throws me off.