Amidst the incomprehensible tragedy of the tsunami in Asia, also saddened to hear of the death of Susan Sontag from cancer. I didn't always agree with what she wrote, but she was an excellent, provocative essayist and had a profound influence on critical studies of the uses to which words and pictures are put.
On a happier note, just discovered Julia Darling's website. Julia is a poet and a novelist, and has written very well on the experience of having cancer. A look at her weblog shows how admirably focused she must be to concentrate on her writing (and she's involved in a LOT of projects) in spite of undergoing treatment.