Ebook reader with great screen and no format lock-in?

Why not just stick with the PDA? It highlights, takes notes, stores dozens of books, has the option of a dictionary, and holds mp3s. Plus many models have wifi access. I carry mine everywhere, I have an Axim X1. The screen is small, so one paperback page becomes 6 or so ... but that doesn't really matter to me -- at least it fits in my pocket.