The best way of tagging classical music has been a matter of debate for some years. There have been some improvements in both software and metadata since the days when classical music lovers were told to tag composers as artists and works as albums. In particular I am a fan of Muso which integrates well with Logitech Media Server and allows for proper structuring of compositions and a rich set of metadata.
I have developed a tagging scheme to (in my view) optimise the way in which Muso and LMS work together and I am very happy with the result. There are two versions - a really simple method that is easy to implement and a much "richer" method that requires use of Mp3tag (via a custom-built action) to keep everything in harmony.
A complete description is provided at my website. Any suggestions for improvements (or bug detection) can be posted to this thread or the one in the Muso forum.