This DragonCon 2012 cosplay compliation video by beatdownboogie is absolutely fantastic. Besides the fun cuts, in-the-moment poses/character acting and perfect music, I really enjoy the hundreds of impressive cosplayers featured above. And they're all having so much fun.
You can catch some awkward, hilarious moments that make me feel like I was a part of the show. A really awesome watch.
DragonCon 2012 - Epic Cosplay [YouTube, thanks David!]