I used a recording of Ian Bostridge singing Schubert's Die Schöne Müllerin (the Hyperion Schubert edition, vol. 25) for my Introduction to Theory class at DePauw's Vocal Arts camp. I've used the recording before, but realized this time that I really, really like it (the recording won the Gramophone solo vocal award for 1996). Bostridge has a very clean, yet sweet and full tone, impeccable diction, and a very creative yet natural sense of phrasing and interpretation. He doesn't resort to cheap theatrics like overblown dynamics or extreme rubatos to make his point, yet expresses the lyrics much more than many singers. Even more impressive, Bostridge has a Ph.D. in history from Oxford, and is a published author and respected authority on witchcraft. It was only after doing a post-doc at Oxford that he decided to pursue music as a career, which he has done very successfully. Here is a short bio.
More musicians need to educate themselves in more things than music; it can only help give their performances or compositions more depth. I know some feel that any time spent away from their studies of music will hinder their development. Some even feel that anything other than practicing and applied lessons are a waste of their time. I can only point to Ian and plenty of other professionals who will have full careers because they took the time to become well-rounded as both musicians and people.