"Too bad, you lost your machine."
F-Zero

“Mama mia!”
Mario

"....." - Gordon Freeman

"HIYA!"- Link

"ENCHANTMENT!!!"

-Sandal, Dragon Age Origins

“Godbye... Joanna Dark”
Dr. Carol, Perfect Dark N64XBLA

I changed my mind:
"All your base are belong to us." -Zero Wing

“When the gatekeeper to Hell asks who sent you, tell them it was Shinobu Jacobs.”
Shinobu Jacobs, No More Heroes: Desperate Struggle

"I need to get to this woman's bottom...I mean, to the bottom of this woman!" -Phoenix Wright

"terminated" -Final Fantasy _{don't ask why, I honestly don't know}
"I am Error." -Zelda 2

"Huzzah!"
Balrog, PC version of Cave Story

"You´re good, but I´m bettah!" -Star Wolf (Star Fox 64, best voiceacting ever)

“FINISH HIM!!!”
Announcer, Mortal Kombat

I don't quite get why people are obsessed with "I am Error". It's just the dudes name. He's telling you his name is Error.

His name was actually was supposed to be Errol but due to the bad translations in the NES days its Error

"Just Go For It!"- Viewtiful Joe
"Lets get it on!"- Viewtiful Joe

"I HAVE CHORTLES!!!!!!!!!!"

Fawful

Fawful: I have boredom...Guests? Now I have...FURY! I say to you WELCOME! Welcome to Fawful's Bean 'n' Badge! In this place beans are like precious treasure milked from a famous cow made of jewels! All who come with beans leave with badges so rare they make mustaches droop with disbelief!
Babies: (cheer)
Fawful: What? The story of Fawful? Your words are not beans. I am not wanting them.
Baby Mario: (jumps)
Fawful: You are like brainless cats that are too dumb to know they are stupid! You have curiosity...but my tale is long, so long it makes babies old and hairy lips grow gray with aging. Do you dare hear?
Babies: (Player selects the option "Um, OK.")
Fawful: Then now you listen! I am here, merchant of badges, only sometimes with fury, but once I had fury at all times. I drizzled rage dressing on the country next door. Rage dressing on a salad of evil! And then the bad men came. Red and green bad men. I had the punishment. Bad punishment with hammers and jumping on my head and the overheat of my ship. I have a little fury even with my remembering...Red! And green! A pair of jumping hammers in red and green who are looking just like you!

I HAVE FURY!

Those brothers of badness! My brain aches at their overalls! I have fury AND headache now! Fawful would be here, reigning over all and laughing at you! ...But no.

SO MUCH FURY!

Stupid mustaches! Hairs like the dirty tail of a horse in a barn built by a farmer who is crazy!
...I HAVE CALM.
(Fawful throws off his red cloak, revealing a white Elvis-like suit)
I am waiting like an elevator. I have the commerce. I run Fawful's Bean 'n' Badge, but...the day comes soon when Fawful rises again, and then no baby's candy has safety! I am counting chickens before they are even eggs, before the chickens are even chickens!

I WILL! HAVE! FURY!

I LAUGH AT DEFEAT!

I FIGHT WITH RAGE!

I HURT YOUR FACES!

Hooof... Heffff...D-Did I...have insanity?
Babies: (surprise)
Fawful: Did I...have evil? I suppress the fury, but sometimes... The fury has me. Red and green puts the fog of rage in my eyes, and my mind goes crazy.
Babies: (surprise)
Fawful: P-Please... I will be fine. No worrying for Fawful. We talk of beans. Beans and badges... We begin trading! What are you wanting?

Probably one of my favorite quotes of all time (from Mario & Luigi: Superstar Saga)
Oho Jee: That's OK I only pretend to be dead. Ha ha funny.

It looks vaguely like your hynie after it's been chewed out by your boss.
Narrator- Space Quest IV

"Tactical Nuke Incoming! Its over!"- Soldiers in MW2. ( Dramatized version by the Spestnaz )