I'd have to go with 80s Christian Metal group, Stryper. Saw them in 2003 in Pittsburgh on their comeback tour. It was a small gig at the Hard Rock Cafe so they were easily approachable. Got photos with them all and got them to autograph my 'To Hell with the Devil' CD.
Most everyone else somewhat famous I've met have been Pro-wrestlers. Jake "The Snake" Roberts, Raven, Disco Infrerno, Jerry Lynn, Sandman, Christian, King Kong Bundy, Balls Mahoney, Axel Rotten, Loki, Kudo, Christopher Daniels, and the Blue Meanie are the most notable ones for me. Have autographs and photos from a few of them.
Also met Country star Travis Tritt, but that was a complete accident. Didn't even know who he was until someone told me (because Country Music is a plague on society).