Final Fantasy VII FTW

All the FFVII ones are so obvious though. Everyone has played that game, unlike Mario!

"Can you believe a great battle was once fought here, on the very ground that you now so peacefully graze? Many men died. Some did it for freedom and some for country. Others did it just because they had guns. It's a crazy world, isn't it? Hmmm? Don't you think it's crazy? Hey, I'm talking to you cow. It's because of me that you're not talking French right now. Shame on you, ungrateful cow."

"One time you awoke obsessed with the idea that *I* was your skull and chased me around the Spire trying to shatter and devour me. Luckily, you were crushed by a passing cart in the street."

just about everything from the Legacy Of Kain series

Kain: Thirty years hence, I am presented with a dilemma... let's call it a two-sided coin. If the coin falls one way, I sacrifice myself and thus restore the Pillars... but as the last surviving vampire in Nosgoth, this would mean the annihilation of our species... Moebius made sure of that. If the coin lands on the reverse, I refuse the sacrifice and thus doom the Pillars to an eternity of collapse. Either way, the game is rigged.
Raziel: We agree then that the Pillars are crucial and must be restored.
Kain: Yes, Raziel, that is why we've come full-circle to this place.
Raziel: So after all this, you make my case for me. To end this stalemate, you must die so that new Guardians can be born.
Kain: The Pillars don't belong to them, Raziel... they belong to us.
Raziel: Your arrogance is boundless, Kain.
Kain: There's a third option, a monumental secret hidden in your very presence here. But it's a secret you have to discover for yourself. Unearth your destiny, Raziel. It's all laid out for you here.
Raziel: You said it yourself, Kain... there are only two sides to your coin.
Kain: Apparently so, but suppose you throw a coin enough times... suppose one day, it lands on its edge.

"I am matter....

  I am antimatter....

  I can see the past.....

   I can see the future....

   I consume time....

   And I will consule you!!"

Culex - Super Mario RPG

Haken: What the hell is that? Some kind of vine?
Aschen: Maybe it's a tentacle, molesting the planet itself.

Super Robot Wars - Endless Frontier Saga

Whatever the orc peons or the acolytes said when we clicked on them in Warcraft 3 lol

"Work, work!"

"My life for Ner'zhul."

Best quote from the one who kicks ass and chew bubble gum. Joning speech to act nukem's way FTW : 

'I'm gonna rip ur head off and shit down ur neck'

http://www.youtube.com/watch?v=cgRRweh1jsg