Yeah, i agree about DC One Million. I'm not sure if Seven Soldiers counts but that was another great one. Final Crisis was not quite as great so i wouldn't say even Morrison is batting 1000 but for my money he is most likely to pen an event that doesn't come across merely as a vehicle for higher-ups to adjust continuity to their liking. If 52 counts that was great too (and once again Morrison was involved!)
Can't say about the worst as i haven't read all events but thought Infinite Crisis wasn't very good.