I much prefer to hang at the bars on the casino floor and talk to whoever comes around. They let you smoke, the music is better and less deafening, and you'll meet more interesting people.
There's a big element at DEFCON of people who read way too many Neal Stephenson novels, got a utilikilt and a mohawk, and are roleplaying as haxxors. Escape that. Find interesting talks. Find feds, because they're getting paid to do security work and are often damn good at it. Don't feel like you have to go to every talk.