One of the books I picked up in London was A Blink of the Screen, a collection of short fiction from Terry Pratchett. While anthologies aren't usually my thing, this is Pratchett.
Anyway, the collection is roughly 2/3 non-Discworld, and 1/2 Discworld, although a few of those are things written for other sources. (In particular, a synopsis written setting up the Discworld boardgame that eventually got written in book form as THUD!.)
There are some stories that are really really good and stick out in the not Discworld section. Like "Turntables of the Night", in which DEATH goes to a Disco. The entire conversation between the anthropomorphism of Death and a DJ discussing artists they collect made this worth the buy. In another really odd one, "Twenty Pence, With Envelope and Seasonal Greeting" is a bit like if HP Lovecraft wrote a Christmas story. (Seriously. Much of the story is recounted by someone observing an insane postal worker driven mad by the world turning into Christmas Cards.)
In terms of the Discworld section, the big one is the near novella that is "The Sea and Little Fishes" (which has deleted material in the Appendix). It concerns Witch Trials, and a committee of witches trying to convince Granny Weatherwax not to enter so someone else can win. Esme's way of dealing with this is delightful. Another standout is "Theatre of Cruelty", in which the Night Watch tries to solve the mystery of a dead puppeteer. Including the absolutely wonderful interview with a witness, once again DEATH.
One really interesting story in here, "The High Meggas", is basically the origin of The Long Earth. One of the protagonists here shares a name with the eventual protagonist of the series, but past that the resemblance to what came later on is superficial.
And of course, there's the lyrics to the Ankh-Morpork National Anthem, written for a BBC Radio programme about various National Anthems. Which was then set to music and sung by the Scots.
Bonus joke is Pratchett's observation that most folks remain shocked to learn their anthem has more than one verse, so the second verse has a bunch of mumbling followed by a few words, as if the Soprano singing it remembered the ends of the phrase.
I miss Pratchett. I'm always glad to have a reminded of why I miss him.