Some of mine:
1. Steel vs. the Eradicator - a guy who built his own powerarmor versus a Kryptonian weapon. Yet Irons has shown he can throwdown more than once.
2. Blue Devil vs. Etrigan the demon - a moderately superstrong guy versus the son of Belial. But whenever these two go at it, Lobo's pal the demon can't seem to drop Dan despite numerous encounters.