For me, I've been dabbling around, but I recently heard Czech and it sounded absolutely beautiful to me. It seemed to have a certain flow to it.
EDIT: Thank you everyone for your replies! So far, I'm seeing a surprising amount of German in this list. Answers seem to be based on the amount of grammar learned, and whether the language has another meaning to the person. Truly "beauty in the (ear) of the beholder"! This is really fascinating