Castle was seemingly made with me in mind: It's got a Mentalist-style puckish main character and good-girl cop combination and it's about a novelist. For the most part, season one delivered on this promise, although it was lighter than I would have liked in terms of character development, especially for the secondary characters.
Richard Castle is basically a hot (and probably also less arrogant) fictionalized version of James Patterson--a bestselling novelist with a colorful past, known for his pulpy productivity and amorous adventuring. When a killer starts murdering people as described in several of Castle's books, he is questioned by the no-nonsense NYPD detective Kate Beckett. As that case is resolved, Beckett sparks Castle's interest, and he uses his political connections to get himself a permanent place riding along with her in search of new material, which eventually becomes a new series of books featuring the character Nikki Heat.
Castle is an engaging fellow, but I didn't find him as charming as I think I was supposed to. Maybe I should clarify that I do not share the adoration for Nathan Fillion that many seem to profess on the internet. Castle is very wealthy and apparently free of the cares that plague most of us, although he does share an enormous apartment with his mother and daughter. Most of his best moments, and the glimpses of a possible deeper character, come when he is interacting with his family--worrying about his daughter or sniping with his mother.
Kate Beckett, who is beautiful and reserved, became a police officer as a result of her mother's tragic unsolved murder. She is a restrained fangirl of Castle's work, which provides definite humor whenever he realizes that she's a little too well read for a casual consumer. Stana Katic plays her ably, but is of course gorgeous, which makes her tough NYPD cop character a bit hard to swallow. But of course there's tragic unsolved yada yada to consider. That is how she can be both beautiful and determined!
As for the remaining characters, there are glimpses of interesting possibilities for development. The first season was only ten episodes long, and didn't really have the opportunity to go beyond setting up the Castle/Beckett dynamic, but there are the other members of Beckett's team, detectives Esposito and Ryan; Beckett's boss and the adorable female medical examiner; and of course Castle's family members.
In general, the tone of the show is light and quippy. The crimes that Beckett and Castle investigate are pedestrian, for the most part, and the focus of the show is on their interaction rather than on the business of crime-solving itself. There are hints that Castle might be able to make some progress on the mysterious death of Beckett's mother, which is something to look forward to in season two--once she forgives him for reopening the case.
I tried to listen to the first Nikki Heat book on CD, and the narrator's voice was so wrong and annoying that I had to stop. Whether I pick up the printed book (or its sequels) to get the full Castle experience remains to be seen.
I don't have time to watch bonus features and meddle with things like that, which is why this is a TV review and not a DVD review. But I'm sure they were lovely.