I now have both Thaxted from Jupiter from The Planets by Gustav Holst and Sabre Dance from Gayaneh by Aram Khachaturian memorized. (Note: This does not mean they are without mistakes. It merely means I don't strictly need the book to practice.) They both are arranged for solo piano by Christopher Norton, as was Montagues and Capulets. (And in my opinion, he needed better editing on Thaxted. It was written more confusing than it could have been.)
Next: Romance from Lieutenant Kijé by Serge Prokofieff*.
Oh, 20th century classics. You are so insane. I love you.
*This is how it was spelled in the book. The alternate version is Sergei Prokofiev, and I don't know which is considered a closer translation or whatever.