Here's what everyone wants to see...the costumes. Most of these people spend a great deal of time crafting these costumes at home. A few here & there are models, but its pretty easy to guess which they are. For everyone else, its more like, "I've always wanted to be a......." and that's their dream come true for the day. As far as the most popular costumes, I'd say there were a ton of steampunks and Transformers.
My favortite shot is Rorschach from The Watchmen taking a photo of Super Homer.