Some of the things you say when taunting are great (not just what they say, but HOW they say it)...
"I'm gonna leave you in bits, like the Ice Truck Killer" (Dexter)
"I am teh pwnerer, bitches" (Jeremy, Pure Pwnage)
"BOOM! HEADSHOT!" (Doug, Pure Pwnage)
"The day is mine!" (Celebrity Jeopardy)
"Frakking Toaster" (Battlestar Galactica"
"I'll bite your legs off" (Monty Python and the Quest for the Holy Grail)
"You tattering crap dragon!" (no idea!)
"You'll rue the day!" (Real Genius)
"Don't make me slap you!" (South Park)
"I got a present for ya!" (Command and Conquer)
"Its a good day to die" (Star Trek 2: the Wrath of Khan)
"Whats up? No saving roll?" (random D&D thing)
"HAHA!" (Nelson from the Simpsons)