Now, I have talked to a few people who have told me that they feel as if they didn't quite get the big deal with Terry Pratchett. They tried reading the Discworld books, and just didn't care for it. I wonder if those people started at the beginning - because in the first couple of books, Pratchett is clearly still discovering his style.
So if you've tried to read the Discworld books from the beginning and just haven't been able to get into them, I recommend you start with Wyrd Sisters. You don't have to start from the beginning. The books do not carry on a greater storyline - there are times when characters from one book show up in another, but they are not telling a bigger story in which you are missing out if you fail to read those others. There's no need to be a completionist. You have permission to start wherever you like.
But the reason you should start here is that Wyrd Sisters is so spectacular. It spoofs Macbeth brilliantly throughout the story - imagine Macbeth from the witches' point of view, if the witches were actually reluctant to meddle, or even reluctant to be in a coven. It has also been the funniest so far. Give it another shot. The payoff is worth it.
--------------------------------------------Next up I'm reading The Man Who Was Thursday by G.K. Chesterton. All I really know about this book is that lots of writers I like recommend it (which is certainly good enough for me). All I really know about Chesterton is that he inspired Gilbert (aka Fiddler's Green) in the Sandman comics by Neil Gaiman.