Baseball: Every great that played from the mid/late 80's to mid 00's. I went to 100's of games in that time period even though the closest stadium was a 600 mile round trip.
Basketball: I bought Timberwolves season tickets for the 06-07 season so I could see all the greats of the game in person that season. It is the only time I ever went to basketball games.
Football: Troy Aikman, Emmit Smith, and John Elway
Hockey: What is Hockey?