Well, obviously it's hard to pick one and many of those already mentioned are excellent choices. But, from a pure enjoyment standpoint, I'll have to go with Myron Bolitar. He's always entertaining and hilarious, yet a total Boy Scout.
What a difficult choice. I love so many: William Kent Kreuger's Cork Cochoran, Tim Hallinan's Poke Rafferty, Kellerman's Alex Delaware, Sandford's Lucas Davenport and now Virgil Flowers, Hillerman's Jim Chee and Joe Leaphorn...
But I think I'm going to have to go with Joe Pike. I heart Joe Pike.