Flynn actually using his bard powers to save the day at the end.
Hell, most of the final battle with the Hierophant. From Sir Osric saving Daphne from the Hierophant's Dragon and defying him, to Flynn's aforementioned moment where he saves the day, and finally Daphne throwing her spear at the Heart of Therin, freeing the goddess from her prison.
He may have been cheating, but I'll be damned if Cass whipping out a lightsaber, a shotgun, explosives and a chainsaw against Mort Kemnon isn't awesome.
In the first film, after Ambrose/Magellen has been the only truly useless party member for the entire thing, and Rogan's Sword of Ogre Decapitation has proved equally pointless, it is rather satisfying to see them both become useful when Magellen hits the Shadow with a polymorph spell.
"What did you turn him into?"
Weaver telling Cass their game was the best one he'd played in years in "Hands of Fate"
Myriad beating the Emissary with the Apple of Life and the Largest Turnip