I shoot mainly action with a pair of 580EX II remotes (at maximum zoom) on Pocket Wizard FlexTT5 radios and a 600EX-RT on the shoe (mounted atop the transmitting radio) for fill light. Gels are crucial for whatever flash application you have in mind. Since you can match the ambient white temperature, they make it much harder to tell that you added light. Auxiliary battery packs are critical to keeping the cycle speed up and makiing sure your lights can last a full night.
Mine's a pretty chunky setup - hard to maneuver - and partially driven by the need to switch between long-range action shooting and short range crowd portraits (post-bout celebrations) in seconds. But it gives me shots like this.