what is the best sounding language?
For me it is definitely Italian though I have a soft spot for Slavic languages such as Czech, Polish, Croatian and Russian.
I think it's something different for everyone, but to me Mandarin Chinese (I love the tones!), American Sign Language (it doesn't have a sound but it looks beautiful), and Ukrainian (it kind of sounds like Russian and Italian mixed!) are some beautiful sounding languages.
English with a Southern US accent, French in a Louisiana accent, and Irish but God help you if you try to figure out how it sounds by reading it.