I've been to the Baseball, Football and Hockey Hall of Fames.
Cooperstown (Baseball) was by far my favorite. Granted, I went like 20 years ago, but I loved it. The Museum has tons of cool stuff, and I could have spent hours in the actual Hall of Fame reading the plaques.
Football and Hockey were both very cool as well. Both much smaller than Baseball, but still cool. The Hockey HoF had a fair amount of interactive stuff witch was fun. Also, seeing, touching, and getting a picture with the Stanley Cup was VERY cool.
RB: R. Rice, CJ Spiller
WR: AJ Green