Having attended the SES conference in Chicago last year, I can tell you that it's well worth the price. Not only do you pick up valuable nuggets of information, but you also get to talk to some of the same industry leaders you read about.
But most importantly, you also get to network and put a personality behind the name and face.
I am currently attending the ILM 05 - which is based on local search - and I would highly recommend this conference to anyone in the
seo industry.