Speaking of highly recommending traveling without an ID, on my way back from school last year, I got really stoned in my friend's car on the way to the airport. Me being stoned, I left my wallet in the car, and ended up at the airport with no ID.

I also got to go through the much-faster special screening, but I had to step into a chamber where they puffed you with air. Not for weed scent, for bombs, though I was mildly concerned at the time.

All in all a fun experience. Next time there's a big line at security, I'm going to tell them that I forgot my id. w00t