Two books to be read aloud, for two different reasons.
Feersum Endjinn, by Iain M. Banks - very long, and I wouldn’t normally choose to read a book that long aloud. However, sections of the book are written from the POV of a character who can’t spell - so the spelling is phonetic, and unless you read it aloud (or at least subvocalize), it’s really difficult to understand. I enjoyed the book, but it killed my reading speed on that one.
At the other end of the spectrum: A Rose for Ecclesiastes, by Roger Zelazny. Zelazny routinely has beautiful prose that comes to life when read aloud, but it really shines here. And Zelazny novels are short enough to make this practical.