Themis-Athena's Garden of Books

Hmmm.  Until I read Pyramids two months ago, this one would have been a no-brainer.  Then I met You Bastard ...

OK.  This may be slightly unfair, since Granny simply gets more page time than You Bastard, but:

1. Granny Weatherwax

2.  Runners-up, on an equal footing:

     * You Bastard

     * DEATH

     * Angua

     * HEX

     * The Librarian

Total badasses and hilariously funny, the lot of them -- and all of them can expose humanity's (and society's) utter inanity more effectively with a single word, facial expression or gesture than most other characters even by Pratchett himself.

ETA: AND the Librarian of course, for all of the above reasons.  How could I possibly forget the awesome Librarian of Unseen University?!

(Task: Who is your favorite Discworld character and why?)