"If violence doesn't solve all your problems, you're not using enough." - Largo, Bubblegum Crisis.
"I was defeated... By flying penguins..." - One of many rivals of the good guys in Inazuma Eleven. It's only made more "WTF" inducing by the fact they're playing football.
"So, where is your future now?" - Kenshin Himura from Rurouni Kenshi, after a guy boasted about his "weapon of the future" (a chaingun, back in the late 1800s,) and killed several ninja, but then was screwed by a kunai stuck in the ammo 'chain.' Cue much pain.
Possibly the best scene in Ranma 1/2:
Ryouga: *After accidentally cutting Akane's long hair with one of his flying bandannas, while fighting Ranma.* Go ahead, take your grief out on us.
*Next scene, a very beaten up Ryouga and Ranma are standing there, looking miserable.*
Ranma: She did.
From Slayers:
Lina Inverse: So here's how it goes: You have five options. First, I beat you up. Second, Gourry beats you up. Third, Zelgadis beats you up. Fourth, Amelia beats you up.
Bad guy: And the fifth is I give up and you take me to jail, right?
Lina: Nah, the fifth is we all beat you up. So what's it gonna be?
Lina: Me? I'm just a cute, young, talented magician!
Zelgadis: She's also the poster girl of collateral damage.
Lina: Which side are you really on? Ours or the enemy's?
Xellos: Yes.
From Lyrical Nanoha:
Nanoha: You say I'm a devil? I don't mind. It just means I'll have to use my demonic powers to get you to listen to me.
Vita: *After finally reaching the enemy ship's core, which she has to destroy, she finds it has a defense system with enough turrets to bring down an army. She's bleeding from a hole in her stomach, tired after facing a horde of enemy robots, and knows no help will arrive, since her allies are all busy. Basically, she has little chance to make it out of it alive, or to even destroy the core. What does a badass magical girl say in such a situation?* Bring it on.