I think that Korean sounds just wonderful. Something about the prosodic pattern of it makes me happy.
Additionally, I really love the Busan dialect, but I wouldn't say that it's beautiful. Just, there are remnants of an old tonal system in it that make it really interesting to listen to, and I find it fascinating from a linguistic standpoint considering how it differs from the standard. I would really love to learn that dialect just so I could study its inner workings, ahaha.