Well, opera is a given, since it's the profession I hope to exert!

Most Wagner, Mozart, Strauss and Rossini.
Thrash, Folk, and Neoclassical metal, some goth, blues, jazz (
with vocals, modern, progressive jazz can be as technically brilliant as it is, but it also makes me go to sleep in about 30 seconds.)
And however you classify artists like Marty Friedman, Paul Gilbert, Buckethead, etc. Shred? Meh.