Engineer:
"Take it like a man, shorty."
"I told you, don't touch that darn thing!"
Spy:
"I never really was on your side."
*snorting laughter* (Domination laugh, right?)
Scout:
"EAT IT, FATTY!"
"Lotta good that gun didja!"
Medic:
"I am ZE UBERMENSCH!"
"Oops! Zat was not medicine!" *snaps glove*
Sniper:
"Wave g'bye to your head, wanker!"
"That helmet ain't gonna save you."
Soldier:
"If god had wanted you to live, he would not have created me!"
Demoman:
"They're going to bury what's left of ya in a soup can!"
"Oooh, they're going to have to glue you back together... in HELL!"
Heavy:
"Cry some more!"
*insert rest of already-mentioned hilarious quotes here*
Pyro:
"Mmmph mmmrph mmrph mmmmph!"
"Hudda hudda hudda!"
...and that about covers it.