It's probably Hearns Hagler because they were so highly ranked and were in their prime. That added to it.
Too many to pick from. Pintor/Gomez, Sanchez/Gomez, Vasquez/Marquez, Gonzalez/Carbajal, Castillo/Corrales, Gatti/Ward, Holyfield/Bowe, Hussein/Arce and on and on and on...
depends how you define a brawl, imo. rosario - ramirez II was pretty wild. of course gatti - ward was brawl more than anything barrera - morales I is probably one of the best "brawls" i remember, jsut because of both guys skills. though tommy decided to box more in the 2nd and 3rd, hearns and hagler threw out strategy in the first round just to rip each other to shreds. one of the best rounds in boxing. the exchanges in duran - leonard I during the latter rounds were amazing as well.