Since Going Postal is one of the few Pratchett's I have actually read, I was sort of OVERJOYED to see that it had been made into a telething. Especially since, oh my goodness, Richard Coyle is perfect as Moist. And then you've also got Charles Dance and David Suchet. (I forget that Suchet is English almost all the time, but, by God, his voice is sexy when he's playing evil. That's right, baby, I just had impure thoughts about Poirot. ALSO, you all know how I feel about hammy archvillain acting. I kind of love it, when it's done by an actor I know can also be startlingly subtle.) Also, Stanley is amazing, and Ian Bonar reminds me of Lee Ingleby.
I thought it was really well done. I probably shouldn't be surprised, since I liked the Sky production of Hogfather (I haven't watched The Colour of Magic yet.) It likely helps that I'm not a hardcore fan or aficionado, but yeah, I really liked it. It had the tone of the book wonderfully and, considering, as a telething, it was a lot shorter than the book could be, managed to fit in a lot of what made the book awesome.