I'm about 1/3 of the way through Francine Prose's Caravaggio - which means I'm about 50 pages in. I love Prose's writing style - I read her Lives of the Muses a while back and loved it - and would definitely recommend it, but only if you really love Caravaggio OR you can get it on sale. I think the cover price is around $25.00 and it's only about 150 pages long. I got it from the History Book Club as a set with another book about Caravaggio, The Lost Painting by Johnathan Harr and the price for the set was much lower than cover price.
In a weak moment at Borders the other day, I bought Ross King's new book, The Judgment of Paris: The Revolutionary Decade That Gave the World Impressionism. He also wrote Michelangelo and the Pope's Ceiling, which I LOVED and Brunelleschi's Dome, which is next on my list. I guess I've got an art history theme going here!
I couldn't read Sharon Rocha's book either. The last just desperately sad book I read was Arthur Ashe's autobiography. I got to the letter to his daughter and just lost it. The other biography that had me was the book Gilda Radner wrote not long before she died (I think it was called It's Always Something). She kept talking about getting better.