Amusingly enough, this turned up recently as a topic on RPG.net, and though what constituted "evil defeated by love" got a bit broad, stories included

Stardust
Stephen King's IT (well, underage group sex, anyway)
The Fifth Element
Yellow Submarine
The Princess Bride (which also fell into that subset of "love can rescue/resurrect a fallen hero")
The Shining
Star Wars: Return of the Jedi