I haven't been to too many Cons. But being in Central California I have been to Baycon twice and when Worldcon was in Reno, NV it was close enough for me to drive to.
One speaker I have heard at each of these Cons was Marty Halpern. He's an editor with a ton of Science Fiction and Fantasy editorial experience. His blog site is at:
I was just there to copy the link address and he had posted an open letter to Idie Author's by J. M. Gregoire. I just began to read it and as usual, the stuff on Mr. Halpern's site is worth our time to read; whether you're a writer, reader or editor.
I've found his presentations at the cons as some of the most interesting, informative and authoritative lectures I've come across since trying to join this community of writers. I'm going back to his blog to pick up the link to the rest of that open letter. You should too.