My niece brought these to me on her last visit: I had read some of the later books in the series, but was content to read them in the order I found them rather than in what passes for chronological order. Can’t recommend them too highly, in or out of order.
“The Color of Magic: A Discworld Novel (A Discworld Novel)” (Terry Pratchett)
“The Light Fantastic: A Discworld Novel (A Discworld Novel)” (Terry Pratchett)
“Mort (Discworld, Book 4)” (Terry Pratchett)
“Equal Rites: A Discworld Novel (Discworld Novels)” (Terry Pratchett)
“Sourcery (Discworld Novels)” (Terry Pratchett)
“Guards! Guards! (Discworld, Book 8)” (Terry Pratchett)
“Wyrd Sisters (Discworld, Book 6)” (Terry Pratchett)
“Small Gods (Discworld, Book 13)” (Terry Pratchett)
I had read these already:
“The Truth (Discworld, Book 25)” (Terry Pratchett)
“Thud!: A Novel of Discworld (Discworld Novels)” (Terry Pratchett)
“Night Watch (Discworld, Book 27)” (Terry Pratchett)
“Reaper Man (Discworld, Book 11)” (Terry Pratchett)
“Feet of Clay (Discworld, Book 19)” (Terry Pratchett)
“Carpe Jugulum (Discworld, Book 23)” (Terry Pratchett)
“Hogfather: A Novel of Discworld” (Terry Pratchett)
“Hogfather: A Novel of Discworld” (Terry Pratchett)
The books for younger readers (Maurice and his Educated Rodents, The Wee Free Men and A Hat Full of Sky) are excellent as well. The even younger Bromeliad Trilogy never caught on here: the first one, Truckers, seemed OK, but the others languished unread.