I recently purchased Heretics of Dune and God Emperor of Dune. I’ve owned these in paperback for a number of years but I decided to buy the digital version because, well, the more and more I use my ereaders the more I like them and they take up less space in my house. Also, I plan to make good on my promise to myself to start the series and read Dune, so these books will soon follow. I already own Dune Messiah and Children of Dune in digital format, so next will be Chapterhouse: Dune.
Also I purchased A Call to Duty by David Weber and Timothy Zahn, mostly because I noticed it dropped in price, plus I’ve heard nothing but good things about the Honorverse series of books by Weber so those will be on my reading list at some point in the future as well.