Those covers are absolutely brilliant. Love every single one of them. Do I dare to say it... aah well but just as well do it. They're better than Kirby's as covers. Josh makes illustrations, not covers (and we all agree they are superior as illustrations).
In regards to the Maskerade cover, is it just me, or is it an allusion to Rafael's The school of Athens? With Granny pointing up? If so, then it's a terrific comparison: Granny/Nanny as Plato/Aristotle. Two completely different ways of handling the witchcraft, no?
Impossible to pick a favourite... Next time I'm in France, I'll make sure to buy one! (with the bonus of practising my fantastic french... ahum). Can't wait for Hogfather!
"...my father is the Emperor of Klatch and my mother is a small tray of raspberry puddings."