I'm always happy to recommend songs, so just let me know.
I will tell you a lil about Opeth. They are a pretty interesting band with several different sounds. Early on they were very death metal, but most albums still had one or two tracks that were either instrumental or almost kind of folksy. Most tracks include a mixture of clean and growling vocals. There is even an album that is only acoustic (Damnation) with clean vocals. Their newer albums do not have the growling vocals either.
Their diverse sound and each song being a bit of a roller-coaster is why I enjoy them so much. I would recommend the songs Harlequin Forest and Bleak. If you check them out, let me know whatcha think.