He was one among the few great living condutors. I'm just listening to his Dvorak, Janacek and Suk, but also to his Beethoven, Mozart, Haydn, Haendel, Brahms... You think to know very well a work, then you listen to one of his interpretations and you always discover something new, often exciting. And how better orchestras played when he was on the podium. Just compare the work of the Philharmonia with him (I'm thinking about Schubert's "Great" and Dvorak's Seventh and Eight) and what they do, for example, with Salonen.
Sadly, His Mahler legacy is small: the First, the Fifth, a wonderful Sixth (one among my reference recordings), the Wunderhorn on CDs and a Fourth with the Philharmonia that is available as download (it should have been released on CD on December 2009, but they preferred to release Salonen's weak Ninth). I regret that he did not record Mahler with the Czech Philharmonic and that he did not record enough Suk (when I saw that the Scherzo of Asrael was on schedule for the Czech Philharmonic concert celebrating Sir Charles 85's birthday, I hoped for somehting to come on CD).
For knowing something more about him through his own words:
http://www.classicstoday.com/features/f1_0200.aspRegards,
Luca