So basically what comic character, any character would you like superman to up aganst ? Doesn't matter if he wins or loses as long as the fight is truly epic. For me I would love to see superman go up against Thanos that fight would be brutal.
aquaman, hawkman, captain marvel, black adam, martian manhunter, orion, hercules, thor, spectre, captain atom, majestic, apollo, daxamites, icon, hardware.
Spectre beat him, Aquaman loses, Hawkman without the Claw of Horus doesn't have much of a shot. But this isn't a battle to debate :P