I've got a couple I can add to the list!
For starters I hear the guys of Rush are really nice. Judging by their interviews they seem very humble and honestly care about their fans. Plus I have some friends who have met them and said that they're really cool.
Another one I've heard being a nice guy is the godfather of shock himself Alice Cooper. Since the man lives in my hometown of Phoenix, I've heard that there have been many appearances of him in public. Apparently you can meet him anywhere. My mom said that one of her customers at work met Alice at a movie theater. My grandpa has even met the guy. I've heard nothing but positive comments about him, saying that he's very cordial. The type of guy that would strike up a friendly conversation with a stranger. For someone with his status that is really awesome!