I almost added a caveat to The Towering Inferno. It's kind of like Rocky I to all the Rocky's that followed. The first one did it best. AFAIK, The Towering Inferno was the first. Or at least 'first' that was a cut above and brought a spotlight to the genre.
EDIT: I feel I should add that Rocky I was easily a better movie than Towering Inferno (IMO)... I wasn't making that type of comparison. I don't consider TI as 'bad' though.