I love me some Dances. Quiver Dance, Dragon Dance, Fiery Dance, Swords Dance, Petal Dance, Rain Dance, FeatherDance, Teeter Dance, Lunar Dance. If it learns a Dance, then I will catch it and make it learn a Dance. Quiver Dance is definitely my all-time favorite, though.
Least favorite is simple: DynamicPunch. Of course it'll hit when you use it, but it's a waste of a move slot without No Guard for me. Zap Cannon would be the same, but I've never been against it.