They are all good books, and none (outside the series') are order dependent. I tend to like longer books, so be warned! haha. Long books in long series? Sign me up!
If you are wanting to scratch a fantasy fix, you can't go wrong with Brandon Sanderson. He is really good at world building, and his books are very immersive. His 'The Stormlight Archive: The Way of Kings' is the first book in the Stormlight Archives, my favorite series of his. If you like to save the best for last, you could do his Mistborn series or Elantris to start.
If you are wanting science fiction, The Hyperion Cantos is my all time favorite series there. It is four books: Hyperion, The Fall of Hyperion, Endymion, The Rise of Endymion.
Daemon and Freedom are shorter (as in, only two books in the series, and not too large each). So if you are wanting a bit less of an investment in listening, they are fun. It changed what I view as the hopeful future of AR by the second book.
But, really, all the books and series I listed are some of my top picks. I can go on. I enjoyed all of the Enderverse by Orson Scott Card, which has like 16 books with 3 to be announced (start with Ender's game, and go onto the speaker series, then the shadow series, and on from there). I enjoyed Jim Butcher's Dresden Files (kinda more young adult fantasy, but just fun) where the main character is a wizard detective in modern day Chicago. Jim Butcher's Codex Alera was decent too - a world where everyone has magic but the main character. The Wheel of Time series (some folks don't like the slow down in the middle of the series, but I still enjoyed it), and the list goes on!