This will be interesting tonight.
At least half a dozen pieces I'd love to own... if I had $5+ million to spare. The Calder mobile (#39), at least one of the Hockney's (#17), the Georgia O'Keeffe street (#34), and the centrepiece of the auction, the large Gerhard Richter (#8). I also love the early Rothko (#43).
I'm guessing the Richter will go for somewhere just shy of $40 million. A similarly sized Abstraktes Bild sold at a previous Sotheby's auction in 2015 for $28 mill, and I think the current one is more interesting. And a smaller one (owned by Eric Clapton) sold at Christie's in 2016 for $22 mill.