I checked this show out in 2009 because I was curious about the protagonist being a writer. Although the first season has some twitchy moments, I have to congratulate the creative team, because I've lost count of the times I found myself echoing Castle in his "writer" mode. There were even times I said his lines before he did. The most compelling character for me, though, is Kate Beckett, and she's the real reason I decided to tune in for season 2. I wanted to know what happened to her and if she found her mother's killer. I'm not sure at this point that we'll ever have the answer to that question, but I'm definitely glad I stuck around. Season 2 was top notch, and I'm eagerly waiting to see where things will go in Season 3.
Castle/Beckett (What else?)