I LOVE Superman Tonight. One of my all time favs. I argue with myself though whether I consider it a ballad or a mid-tempo song. It's kinda both in different places.

I also adore Into the Echo, and I've been listening to Real Love more and more lately. Then there is Strangers, Walk Like a Man, I Am and These Open Arms which I also enjoy.

I would say though, that in the typical sense of a ballad, either Make a Memory or Thank You For Loving Me was the bands last great one.

The best one of all time though, gotta be a close one between I'll Be There For You and Bed of Roses (Always gets the bronze IMO).