Joss Whedon (50) - Writer. Director, Producer. His current credits include The Avengers and Avengers: Age of Ultron, two of the biggest movies. Ever. Past credits include Buffy and Firefly among others. He is a third generation writer for TV and the movies. What more do I need to say? Amazing awesome.
J. Michael Straczynski (60) - Writer and producer. Pulled together Babylon 5 continuity despite some vast corporate adversity. Has done comics, animation, all the good stuff. (Who ya gonna call? The Real Ghost Busters cartoon!)
Steven Moffat (53) - Writer and producer. Currently head writer for Doctor Who and has been involved with the new incarnation since it's restart in 2005. He wrote the scripts for the movie The Adventures of Tin Tin and is responsible for the BBC show Sherlock. And don't forget, he's Scottish. The accent alone will be worth having him over for dinner.
If Mr. Moffat is not available I'd pick Russell T. Davies (52) - Former head writer for Doctor Who and was deeply involved with the series Torchwood. He's Welsh, so he might like some of my obscure references. Maybe not.
N. John Smith - I'd love to have someone involved in the StarGate series, another well-crafted series, on the list. Smith was the one with the longest tenure so I picked him.
If Mr. Butcher isn't available I'd pick Gregory Widen - He sold a story that was made into the movie Highlander. Then the concept went viral before that was even a legitimate term. It spawned additional movies and a television series, none of which he wrote or was involved with that I could see. I’d ask the same sort of questions about the changes to his ideas.
Who did I forget? I'm sure there are plenty, but for now this will be a good start. Besides, I'm not sure where I could host that many people, especially if they all bring wives, girls friends or guests. (My guest would be romance writer Samantha Lucas. You should check her out!)