I'm not that big a fan of pure black metal. It's often good music, but I like the tweaked forms of the genre more. My absolute favorite black metal band is without a doubt Dornenreich. Their album Her von welken Nächten is genious. Bitter ist's dem Tod zu dienen is great too, but I'm not even sure it could be classified as black metal. Check them out if you want black metal with violins, cellos, acoustic guitars and really unusual vocals.