LOVED Canticle for Leibowitz! One of the best post-apocalyptic 'they don't learn' novels ever. Have you considered adding 'Folks from the Fringe?' or 'Lucifer's Hammer?' Love S.M. Stirling's world, as well, although his last few books have been un-edited and it showed.
Canticle was great! I haven't read Folks from the Fringe or Lucifer's Hammer so that's why they're not on the list. I'll add them to my to-read pile.
Folks from the Fringe is a collection of inter-related short stories by Orson Scott Card. Lucifer's Hammer is probably THE apocalyptic/post-apocalyptic asteroid hitting the earth scenario (I recently had the privilege of meeting one of the two co-authors Jerry Parnelle). I think once you read them, you'll want to add them. If you enjoyed Canticle, you'll enjoy both of them.
Awesome! Thanks for the heads up!