Martin definetly seems like an awesome guy, someone who would be great to go to the bar with and knock back a few brews. He was happy to take a picture with me and my wife and to sign our book with "To Elijah and Leila, I hope you do better than Ned and Cat!" (I had wanted Jaime and Cersei but my wife said hell would break loose if I got that)
One small note, when I got my books signed I noted that I loved all the other licensed products including the CCG and board game. I also noted how both were like the books with all the scheming, ploting, and backstabbing and joked that many a friendship were ruined because of the board game. He responded by saying he had played the board game several times and "lost every time." He also joked that there should be a rule that if you INVENTED the series a board game is based on you could never lose!
Like I said, he seemed like a simply awesome guy.