I Shall Wear Midnight, people habitually abreviate that one on this forum
However I have been re-reading some of the short stories and found the quote in The Sea and Little Fishes (and I thought it was only me who quoted from the really obscure ones )
I will say, in adition to that however that I actually do own a hard copy of every single pratchett book in existance, even if i can't read them. I make a point of owning them.