It can even be from outside sources if you wish to include them, but I'm talking mostly about the comics. I know the fight against Doomsday in Death of, and the fight against Mongul in the Alan Moore story were classics. Are there others? I've always liked Brainiac, and liked their fight at the end of the Brainiac trilogy in the 90s.
Has Superman ever really had a long drawn battle? I can only think of small fights like the recent one with Atlas. I do like his many fights with Darkseid, especially in the cartoon series JLU. Personally, Superman's greatest battle has been with those red trunks of his. He just can't get a good costume, except for Godfall!