The Discworld series

(FIXME: Explain some things about the universe:)
(FIXME: Update this.)

I own a few of the books in this series. These are it:

The Colour of Magic
This is the first book in the series, and it is starred by Rincewind and Twoflower, the first tourist on the Discworld. Twoflower is a genuine tourist, who never realizes it when he is in danger. There is also the fantastic Luggage, who copes in its own way with any kind of trouble.
The Light Fantastic
This is the sequel to The Colour of Magic. The Discworld is heading for destruction, and the only person to save it, Rincewind the Coward/Wizard, who fell off the Discworld in the prequel. It's a great book, but you need to read The Colour of Magic before reading this one.
Equal Rites
Mort
Sourcery
Wyrd Sisters
As often happens in a monarchy, the king dies under mysterious circumstances and the new king is less nice. The infant prince is handed to the three witches, Granny Weatherwax, Nanny Ogg and Magrat Garlic who hands him on to a small theatre group. The new king must be removed, but witches don't like the idea of meddling. This book features a witch who doesn't really know how to fly a broomstick and a song about a hedgehog.
Pyramids
Guards! Guards!
The story is about a small brotherhood (among many others) with a hidden agenda: They want to summon a dragon to restore "the good old times" with kings and heroes and all. They do succeed in summoning dragons, but suddenly things get (of course) out of control. Commander Vimes is set to regain control (and honour) to the Watch, but the odds (and people) are definitely not on his side.
Eric
Reaper Man
Witches Abroad
Small Gods
Lords and Ladies
Men at Arms
Soul Music
Interesting Times
Maskerade
Feet of Clay
This was the first book in the series I read, and I was instantly hooked. A murder has happened in Ankh-Morpork, and Commander Vimes is set to solve it. It's not an easy task when you've got golems running around town, wondering about the meaning of life, philosophising about religion and trying to reproduce. It doesn't get any easier when your squad consists of a werewolf, a gargoyle, a troll and a transsexual dwarf.
Hogfather
Jingo
The Last Continent
Carpe Jugulum
The Fifth Elephant
The Truth
Thief of Time
Night Watch
Monstrous Regiment
Going Postal
Thud!
Making money
Unseen Academicals
The Science of Discworld
The Discworld Almanack