The loudest ones for me were:
The Unforgettable Fire tour at Reunion Arena in Dallas
Zoo TV - Outdoor Broadcast @ TX Stadium
Elevation Third Leg also at Reunion Arena
As far as other bands I've seen - Duran Duran's 25th Anniversary Reunion Tour in '03. I was close to the speakers at that one and I'm suprised I can still hear.
Aren't The Who in the Guiness Book of World's Records as the loudest live band ever?
i'll think that my loudest shows were Popmart and Vertigo