Well, if fun is the criteria: my hiking buddy, Mike. He's got a great sense of humor (his working theory: you die, and I get your gear), and a really positive attitude ("you get hurt, I'm carrying your gear out.") He even makes hiking in the rain enjoyable. He likes using a camera (I don't, and he sends me a CD with the ones he takes.)And, as an ex-SEAL, he doesn't even notice my rock collection!