The marines in the Halo series have always made me giggle.
Halo: Combat Evolved
"THE THING ON THE LEFT! IT'S THE BRAKE!" (If you're driving a Warthog badly)
"Aw, sir, it's more fun shooting them." or "Road pizza!" (When running someone over with the Warthog)
Halo 2
"Don't shoot his head! You'll hurt Cortana, she's a hottie. She's blue... but she's a hottie."
"For a cyborg, he's pretty cute!" (Female marine!)
"That man you killed had a girlfriend with kittens!"
"I ran out of grenades and I accidentally threw my lunch. It's true!"
Halo 3
"Dude! I think I leveled up!" (When giving a marine a powerful weapon)
"Ya know, I really like my job way too much."
"That was amazing! And I only peed myself a little." (Female marine)
"Hey, look at me! I'm shooting dead guys!"
"Sen-effing-sational." (The oh-so-lovable australian marine, with accent)
"Well, I was gonna teabag him, but... everybody's looking."
You know what? I only signed on to this for a college credit and a down payment on a car, but that was pretty exciting."
Tank beats Ghosts! Tank beats Hunters! Tank beats everything! Oh, man, I could do this all day!"
"Can you please save the universe now?" (From an ODST, not a marine, but meh)
"Dude, he's chargin' his Splazer!" (When you're charging the Spartan Laser)