It was such a sucker punch when I heard the news. The amount of my childhood and teenage years I spent in Discworld, I genuinely had to hold back a tear.
If you've not read any Pratchett, or you've only read one or two books, I'd heartily recommend leaping in. Here's the list I posted on Facebook, to the indifference of many:
The Unadulterated Cat:
Non-fiction. If you’ve ever owned a cat (or more accurately been owned by a cat), you should already have read this.
The Wee Free Men:
90% of the characters are Braveheart stereotypes. One is called No-As-Big-As-Medium-Jock-But-Bigger-Than-Wee-Jock Jock.
The Dark Side of the Sun:
A pre-Discworld sci-fi ripping Asmiov. In my head, the film adaptation opens with This Is Tomorrow by Bryan Ferry.
Oh, and a few Discworlds too. In no particular order: Going Postal, Making Money, spiritual predecessor The Truth, Guards Guards, Feet of Clay, Soul Music, Hogfather, Eric, The Colour of Magic, The Light Fantastic, Monstrous Regiment. Personally I started with Interesting Times, which despite being a semi-sequel to The Colour of Magic/The Light Fantastic was distinct enough to serve as a superb introduction to a bloody funny writer.