Thats sort if subjective. Everyone has tbeir favorites and each era or decade has had their favorite. Shelock Holmes, Hercule Poirot, Miss Jane Marple, Sam Spade, Ellery Queen, Phillip Marlow, Perry Mason, Nero Wolf, Lord Peter Wimsey, Columbo, Dick Tracy, Nancy Drew, Hardy Boys, Peter Gunn, Jessica Fletcher, the Harts, Magnum, Adrian Monk. All these and more are ir have been very popular in their time. A few have transcended their time.