Having just attended DEF CON, I can say that I didn't get that vibe at all. The people who were there were very serious about the whole point of it all. I got a lot of value out of it as well.

It looks like Berlin could be a better place for such type of event.

The Chaos Communication Congress is already held annually in Germany, and is well-attended. There is absolutely an appetite for annual hacker/security conferences in the United States (and indeed we already have dozens that are held annually, of all sizes: DEF CON, BlackHat, B-Sides, SchmooCon, etc).

Haha, the ones that actually attended sessions are serious. The other guys just visit casinos and the pool and their boss pays for the trip.

The sessions were all pretty much full. There were many, many people who were taking it seriously. I can't speak to how many people just goofed around the whole trip, as I wouldn't've seen them, but it seemed to be a minority.

Probably true for Blackhat, but I think you're way off the mark on Defcon. It's the highest quality conference I've ever attended, bar none.