The personality who impressed me the most at the convention had to be the guy in line asking Roy Thomas to sign about fifty different copies of the same trading card, despite a good dozen people behind him.
But if you asked me who made the best impression on me at the show this year, the answer would undeniably be Matt Fraction. Not only does the guy have a solid grasp on what makes many of the Marvel Universe's most interesting characters tick, but he's also just so darned cool to talk to. Whether he's running a panel single-handedly (with only Ed Brubaker via cell-phone to back him up), diverting a line to keep the aisles of the convention free, or just chatting... he makes it all look easy, and he does it with style.
He was the writer I was most looking forward to meeting at this year's show. As such, I'd brought more of his books to the show to be signed than anybody else. I brought enough that I didn't feel comfortable carrying them in one shot. After presenting him with the Marvel stuff in the morning, I caught back up to him in the afternoon. The day was wearing on him, and talking with fans (and possibly mugging with Rick Remender seated next to him) was drying out his throat. As he was talking to a convention employee, Official Comic Shelf Photographer Hilary dug into a bag, producing a bottle of the Hilton's best water on the spot. (She was carrying around several of them.) Matt was so grateful, he included the following inscription on my Casanova: Luxuria hardcover:
To translate: "thank you for water. you have saved my life. Fraction!"
And that's the coolest thing I got at the show.