Aside from metal all my other music are jazz, blues, vocals (albums or audiophile CD rips), some Mozart, Mahler and Wagner. If anything's lacking, some jazz and blues tracks actually sound better on some Grados because they make the music sound more "raw" but probably that's just me (or maybe the rough edges of metal tracks just come out more with Grados).
It seems like we have fairly similar musical tastes, with the exception of metal. In addition to the genres you listed, I also love how electronic and deep house sounds with my HD-600 and NFB 12.1. Bass is so tight, punchy and quick.