These are my favorites. I didn't include any TV cops because they seemed like a slightly different category (and one I may need for another TT some day). Therefore, because Castle is about a cop/private citizen pair, yummy Nathan Fillion doesn't qualify. Alas.
1) DAVID ADDISON -- Moonlighting. I have always loved Bruce Willis very much, and never more than in his only TV series. His mystery-solving skills are completely irrelevant to my enjoyment of the show.
2) THOMAS MAGNUM -- Magnum, PI. Tom Selleck was so completely charming as Thomas Sullivan Magnum. He was also very good on Friends as Dr. Richard Burke. If he were to ask me, I'd tell him to skip the drama and stay with comedy. (If you see happen to run into him, tell him that's the Gal's career advice.)
3) JIM ROCKFORD -- The Rockford Files. I love how grumpy Rockford is. James Garner may have had matinee idol looks, but he has the attitude of an old man who'd tell you to get off his lawn.
4) PERRY MASON -- Perry Mason. I didn't watch this show as a child because the theme music frightened me. (Check it out below.) However now I go out of my way to catch it whenever I'm home sick. I love how willing Perry is to almost break the law and taunt the prosecutor. Slightly overweight, well-heeled and always in a suit, he doesn't look like a rebel, but he really was one.
5) ARCHIE GOODWIN -- Nero Wolfe. Orchid-loving gourmand Wolfe may have been the brains of the organization, but Archie (as played by Timothy Hutton) was the legs and the brawn. Streetwise, born to wear a fedora, and with a weakness for a well-turned ankle.
6) ADRIAN MONK -- Monk. Yes, his idiosyncrasies and attention to detail were fun to watch. But I loved the sad subtext, how much Mr. Monk still loved and mourned his late wife, Trudy.
7) ELLERY QUEEN -- Ellery Queen. Like Nero Wolfe, this series is of a specific time. And like Nero Wolfe, it starred a Hutton, this time Timothy's father, Jim. This show was goofy and sweet and deserved a longer run than it had.
8) REMINGTON STEELE -- Remington Steele. I just discovered this show and am belatedly in love with Young Pierce Brosnan. I love how willing he is to make a fool of himself. Remington is really a very bad detective. I'm also loving how Remington and Laura never go beyond necking. I'm not sure why really, but it's romantic nevertheless.
9) BEN MATLOCK -- Matlock. It's a kinda dumb show, but I'm a sucker for Andy Griffith.
10) SPENSER -- Spenser, For Hire. I'm a huge fan of the Spenser books and have a hard time separating the screen characters from the original ones on the page. Robert Urich is too good looking to be Spenser, Barbara Stock seems more like a Baywatch Babe than Harvard-trained psychiatrist Susan, Carolyn McCormick isn't slutty enough to be Rita ... you get the idea. But watched on its own merits, it's a good show. Taut plots and terrific Boston scenery.
11) SHAWN SPENCER -- Psych. James Roday is so good with the fast patter, he's nearly as charming as David Addison. I enjoy the show, too. Am I the only one who has noticed how many really entertaining shows are on USA network?
12) BATMAN -- Batman. No, really! He was so smart and earnest and good and true. Forget Christian Bale, Michael Keaton, George Clooney, et al. There's only one real Batman, Adam West!
13) JESSICA FLETCHER -- Murder, She Wrote. Ok, this show kinda sucks. But I love a plucky middle aged writer indulging in derring-do. And I don't she ever fired a gun. I admire that.