(EDITOR'S NOTE: Unfortunately, this was not one of the show's better moments, technically speaking. I'm a big fan of Fillion's work and everything that could go wrong here, did. It was Firefly fail times a thousand.) Nathan Fillion has paid his dues and, I suspect had a good time doing it. He’s the guy you know and recognize when you see him—oh, yeah, you think—that guy! He was last seen on “Desperate Housewives” as Dana Delany’s beaten-down, much younger husband, Dr. Adam Mayfair. But before that, you’ve seen him in everything from Joss Whedon’s late, lamented sci-fi series “Firefly” to the online sensation, “Dr. Horrible’s Sing-Along Blog.” He also co-starred in the movie Waitress with Keri Russell. Now it appears Fillion has met the role that could be a perfect match for him. He is novelist Richard Castle, the lead character in the new Monday night ABC series “Castle.” The show, which may remind viewers of a certain generation—mine—of “Moonlighting” and younger viewers, perhaps, of “Bones,” airs at 9 p.m. Nathan Fillion • • Listen: (2009) Listen: (2011)