I'd recommend A New Earth as well. Although keep in mind that Tolle is simply writing his own ideas and how he interpret things... As with all of this type of books, read it critically.
I think his core ideas are rather good and interesting, but sometimes when he tries to find connections and applies it to certain circumstances to prove his point, it makes him sound like he's just some kid in a sandbox who has no idea what he's talking about.
It's an interesting read anyway, highly recommended.