I always mean to write a definitive list. Overall I've probably learned the most from Tom of Disputations. A tiny sampling:
Mark Shea: We are not our sins.
Amy Welborn: If the pre-Vatican II church was so healthy and wise, why did it collapse so quickly?
Tom of Disputations: I recall being gobsmacked by his motto capax dei (“capable of God”) simply because he made it sound like holiness was attainable. I also will never forget his saying that (paraphrased) that we are to forgive each other's sins, and often enough that "sinful" behavior doesn't even rise to the level of objectively sinful.
Jeff Miller: A hilarious pic of St. Therese on cover of “Pray Boy” magazine
Julie of Happy Catholic: her saying she reads books while brushing her teeth
Steven Riddle: that he double-stacked books - first time I heard you could do that (not that you'd necessarily want to since it obscures row behind).
Jim Curley: That “Curley in '12” presidential blog stocker/image!
Lee Ann Moraski was a big John Calhoun fan.