With the VU I don't like the lyrics or the singer's voice. Some of the music is ok, some mediocre.
With Joy Division, I can't get my the singer's voice, and I don't like the music. The lyrics? Can't really understand them.
With someone like Bob Dylan, I think he writes good songs, both musically and lyrically, but I can't take his voice.
So I would say the singing and the music are probably the most crucial to me. Like Bagster, if the music is good, I don't mind if the singer sings about ocean cruises or other topics that don't interest me. I do mind if the singer sings about stuff like hard drug use, particularly if he glamorizes it in any way.