By now you will have read that Lorraine Hunt Lieberson has died at 52. I never heard her in performance, but from the recordings I have heard it was clear that she was an artist of the first rank, and her loss is a major one. May she rest in peace. My heartfelt condolences go out to her family and friends.
Addendum, 7 July: Marc Geelhoed has posted a lovely tribute in Slate. Also, The Standing Room has a good round-up of the obituaries and remembrances.