Seeing U2 live at the Super Bowl, I can attest to it being the best ever. Although watching it on TV probably didn't get the same affect because when the showed the names of the 911 victims, their names appeared all over the dome which was not caught on camera which was very powerful being there.
As for the other shows looking at them, I realize that some of the performances were just as bad as the games. I felt the Rolling Stones were awful in their appearance. Aerosmith + Justine Timberlake + Britney Spears = a musical abomination of epic proportions. Aerosmith deserved their own show. Prince was great. I think Tom Petty got snubbed since he gave a solid yet predictable performance. So did Paul McCarthy. I felt they both gave better performances than the Stones who were just off that night. Janet Jackson's performance is only memorable because of the wardrobe malfunction. Many of the others have been long forgotten in my mind because they barely registered at the time (Chubby Checker?!?).