I have a pretty diverse list of music that I enjoy. The one consistant factor is that it is not discordant... I pretty much enjoy all music except country, rap, hip-hop, and most jazz. I love acoustic guitar, and piano.
Some of my favorite groups, singers, etc. are the Strawbs, California Guitar Trio, Judy Collins, and Rick Wakeman. I have seen most of them numerous times in my past, and their music is a source of a great deal of joy to me.
Another of my favorite artists is Leonard Cohen. His music hardly qualifies as smooth and melodious, but his words are extraordinarily powerful, and because of that, I relish his music as well.
I do software support for clients who have IBM mainframe computers, so I really enjoy those songs that are soft and relaxing. It helps me destress each day.