Everything the narrating voice says in every Metal Slug ever. "HEAVY MACHINE GUN" and "WHOA BIG!" come to mind.
Also
"Wololo" - Monk, Age of Empires
"My spleen!" - Enemies, No More Heroes
"AH, FRESH MEAT!" - The Butcher, Diablo
"Stay awhile and listen" - Deckard Cain, Diablo II
"Max, dearest of all my friends..." - Vlad Lem, Max Payne 2
"No, no, no, that's not what happened" - The Prince, Prince of Persia: Sands of Time
Also every line from Commandos: Behind Enemy lines.
UmberHulk said:
I think my favorite is "your not Alexander"
The reason this resonated with me so much is that I never understood who or what the hell everybody was talking about.