Personal Favorites by class:
Scout:
Wave goodbye to your secret crap, dumbass!
Say goodbye to your kneecaps chucklehead!
Soldier:
Kaboom.
IF GOD HAD WANTED YOU TO LIVE, HE WOULD NOT HAVE CREATED ME!
Demo:
I'm DRUNK! You dinnae have an' excuse!
They're goin to bury what's left of ya in a SOUP CAN.
Heavy:
NOMNOMNOMOMNOMNOMOMNOMNOMNOMNOM
I AM AMUSED BY ENTIRE ITTY-BITTY-TEENY TEAM!
... Pretty much everything he says.
Engy:
Whoooo-eeee! Makin' bacon.
*evil laugh taunt*
Medic:
Would you like a second opinion? You are ALSO ugly.
ZIIIIIIIIIIIIIIIIIIIIIIIIM!
Sniper:
That helmet ain't gonna save ya!
Spy:
With my apologies!(after a backstab)