Now It's My Turn

So it looks like the villain has the hero on the ropes. The villain has just unleashed his superweapon - No One Could Survive That, surely!

But wait! The hero's just fine! In fact, that just gave him more confidence. Grinning, he says something like "Now it's my turn!" and proceeds to unleash an even more powerful attack and save the day.

Can also be performed by villains against a group of Redshirts or in response to a Worf Barrage, with the retaliation being a No-Holds-Barred Beatdown.

Essentially, this is Heroic Second Wind minus You Can Barely Stand.

Anime and Manga

Lyrical Nanoha: Nanoha said this during her last battle with Fate after she survived Fate's Photon Lancer Phalanx Shift then responded with Divine Buster. Then she immediately followed that up with a bind and the even bigger Starlight Breaker. Yeah, Nanoha doesn't play very fair. She loves to do this in general, letting the enemy hit her with their best attack, then befriending the fail outta them with a blast that'd make the Wave Motion Gun envious.
Ash Ketchum from Pokémon used the phrase a lot. (Being based on a turn-based game and all...)
Yu-Gi-Oh!: Joey was the most prolific user of this. (It helps that they're playing a turn-based card game...)
Black Cat's Train used this (in the first volume of the manga, IIRC) against a villain, after deflecting the villain's bullets with his custom-made gun, along with one of the freakiest insane faces This Troper has ever seen.
Alucard from Hellsing does this all the time, letting enemies apparently kill him before regenerating. Cue beatdown.
This is basically what happens when Unit 01 goes berserk.
Sasuke Uchiha pulls this during the Chunin Exam Arc after effortlessly, instantaneously dodging Zaku's attack. His turning toward Zaku after knocking him some 20 feet all but says it. The look on Zaku and Dosu's faces confirm it.
In Dragon Ball this phrase is used about 9001 times.
Tengen Toppa Gurren Lagann: At the end of the first Compilation Movie, the four Generals combine their battleships and unleash a Macross Missile Massacre on the heroes... only for Simon to reveal that he blocked the attack with Gurren Lagann's Deflector Shield. He then proceeds to retaliate with a Giga Drill Break laced with a Combined Energy Attack from his teammates, shredding the battleship with ease.

Fan Works

It's used romantically in The Fine Art of Wenching, a fanfic of the live-action Disney version of The Three Musketeers. Beware: slash and historical inaccuracy.
At the climax of With Strings Attached, Paul is hit with a massive inferno attack that disintegrates a table he's holding. And he says: “Do that again! That felt lovely!” Though he doesn't unleash a retaliatory attack on anyone, since he's an Actual Pacifist.

Comic Books

V for Vendetta. Not nearly as blatant as the movie version, nor does he say "Now it's my turn". He does, however, give a monologue after being shot.
Iron Man^[context?]
Deadshot's ~~short-lived ongoing~~^[when?] mini-series:

Deadshot: "You've got one shot. Make it count."
BLAM (Mook shoots and misses)
Deadshot: "That didn't count."

Actually said by Wolverine at the ending of Uncanny X-Men #132. That line and the issue that follows are widely considered a Crowning Moment of Awesome for Logan.
- Kitty Pryde gets an homage to this - same panel, same line - during Joss Whedon's run on Astonishing X-Men, after the Hellfire Club take down the rest of the team leaving her to go up against them on her own.
Marv gets several of these in Sin City due to being Made of Iron. Dwight also got one after being shot in the face in A Dame To Kill For and again in Big Fat Kill when he is blown into a tar pit.

Film

A wordless variant occurs in Goldfinger, courtesy of Oddjob.
River in Serenity says just that before charging on an army worth of Reavers and killing them all. Of course, she didn't take a huge attack or something, only all her True Companions are incapacitated at that point.
- To elaborate, Simon's medical kit is on the other side, and Kaylee is dead without it; nobody has any ammo or really any weapons. River says "No. You take care of me, Simon. You've always taken care of me. My turn.", runs across the room in slow motion, UNARMED, and jumps into a room teeming with Reavers as the blast door closes behind her (she tosses the medkit through right before the doors close). A while later, we see a blood-soaked River Atop a Mountain of Corpses, with two Reaver axes. THIS IS WHY PEOPLE LOVE THIS SHOW.
The movie version of Iron Man also has one of these moments as he's breaking out of the terrorists' camp.
Brad Whitaker in The Living Daylights

You've had your eight, now I'll have my eighty.

- This type of thing shows up in Bond films all the time. In Dr. No, one of the bad guys is sent to kill Bond, but Bond makes it look like he's lying in bed asleep, and the assassin shoots the bed six times before Bond reveals himself. The bad guy drops his gun, and Bond politely interrogates him as he lowers his guard momentarily to light a cigarette. The bad guy quickly picks his gun back up and attempts to shoot Bond. Just watch the scene for yourself to see Bond's sheer awesomeness.
Hellboy during his fight with the demon dogs in the first movie says this, whereupon he knocks the thing around by its tongue
The final battle of the first Blade movie.
- This is the inverted version. Blade has just sliced the Big Bad'a arm off and then sliced his body in half. The villain regenerates within seconds and utters the quote before moving at lightning speed and unleashing a world of hurt on Blade.
The Monkey King in The Forbidden Kingdom says this just seconds after his revival.
In V for Vendetta, V plays this straight by absorbing a colossal amount of automatic gunfire in his final battle, with the aid of some heavy armour. He then kicks butt while the goons attempt to reload, before struggling back to the Tube station with his mortal injuries.
In the beginning of Van Helsing, as the title character is struggling in his fight to bring down Mr. Hyde, he shoots Hyde through the gut with a grapple, and attempts to pull the monster off Notre Dame. Hyde regains his balance, grabs the wire, and yells "My turn!" Then he dies from a serious case of Too Dumb to Live.
Hit-Girl's "I have one of those" about a butterfly knife in Kick-Ass could qualify as this.
Morgana le Fey in The Sorcerer's Apprentice after she dodges some plasma ball threw by the main character.

Literature

Parson Adams in Henry Fielding's Joseph Andrews makes this Older Than Radio.
Older still: Sir Gawain and the Green Knight. They are to fight an unusual duel where Sir Gawain is to hit the Green Knight once anywhere he likes with an axe. Then the Green Knight will retaliate in a year's time. Gawain takes his free hit at the Green Knight and beheads him with one blow. And the Green Knight picks up his severed head and exits the hall with surprising dignity... After thoroughly testing Gawain's chivalry, the magic Green Knight lets him off with the gentlest of grazes.

Live Action TV

Subverted in Dark Angel episode "Fuhgeddaboudit". After Max beats up Alec/X5-494 for a while, Alec/X5-494 says "My turn now, bitch." Max then distracts him, kicks him in the groin and takes him out. Read the full conversation.
Variation occurs in Red Dwarf episode "Terrorform" when Lister, Kryten, and the Cat unload their bazookoids (Blasters designed for mining asteroids) at Rimmer's personified Self-Loathing. When the dust clears, it merely asks "Is it my turn now?" in a bored tone.
Used by Clark Kent in the Smallville episode "Combat", before unleashing a hellacious beating on the superpowered killer, Titan.
Used by Theokoles in the Starz television series Spartacus: Blood and Sand when Spartacus and Crixus are dueling a tag-team against Theokoles, the Shadow of Death (who is totally undefeated). They enter the ring with Crixus announcing "Capua! Shall we begin?" and the two work as a well-oiled machine, fighting as one, to bring the giant down. They turn to the crowd, who chant their names, and then silently fall back into their seats. A medium-wide shot shows the giant getting back-up, and as they turn to watch him, announcing "Capua! Shall I Begin?".
In the Red Dwarf episode "Terrorform", the personification of Rimmer's self-loathing, after withstanding a volley of bazookoid fire, mockingly asks "Is it my turn now?"

Video Games

Final Fantasy IV: "Was it flame? I'll show you how!"
Punch Out examples:
- In the original NES game, if Mac successfully evades Flying Tiger's "magic punches", Tiger becomes dizzy and winded for a few seconds, which is your cue to let him have if.
- During the Nick Bruiser fight in Super Punch-Out!!, you get to hit him as much as you like for the first few seconds without retaliation. For each hit you land, his strength goes up. Once he starts moving, if you were foolish enough to fall for it, his fists play out this trope.
- In the Wii version, during the Title Defense fight with Mr. Sandman, he poses with one arm down and groans "Dreamlannnnnnnnd" before his Big Apple Combo. If you try to punch him, he dodges, yells "My turn!" and delivers a very strong hook.
This is Riku's specialty in the first Kingdom Hearts game when you challenge him during the prologue. If you land too many combo hits on him without thinking, he'll rebound with a spring attack and take off a nice bit of your HP in the process. He even says "my turn!" before countering.
In Super Metroid, the Final Battle with Mother Brain starts out as a Hopeless Boss Fight with the Nigh Invincible villain dealing horrible punishment to the heroine. Then the Super Metroid flies in and sacrifices itself to steal Mother Brain's hyper beam and gives it to Samus. The tide turns quickly with the enraged Samus blowing the hell out of Mother Brain.

Web Original

Used in Super Mario Bros Z when Axem Red blasts Mecha Sonic with a giant laser, doing no damage.

Western Animation

This occurs in an episode of Static Shock when The Joker, Batman and Robin make an appearance. After the Joker is foiled and lying prone on the ground, he calls out for Batman to help, and shocks the hand offered him. Virgil kindly repays the favor with extreme prejudice, after saying, "That was fun! Now it's my turn."
- The actual line was, "That looks fun! Let me try..." Still the same effect, though.
In the Dexter's Laboratory episode "Dexter Dodgeball", Dexter is forced to participate in school gym class and therefore becomes the target of bullies in a match of dodgeball. After several days suffering abuse, he finally invents something to assist him in defeating them. Cut to a CMoA, when Dexter utters the phrase after not flinching when balls get thrown at him.
The Bloom/Icy battle at the end of the first season of Winx Club is basically a contest to see who can do this better.
The Young Justice episode "Agendas" features a fight between two Superman clones, Half-Human Hybrid Superboy and full Kryptonian Match. Unlike Superboy, Match has all of Superman's powers, including flight, heat vision and a greater degree of Super Strength. Superboy is tossed around like a ragdoll until he's forced to resort to a device given to him by Luthor, which temporarily suppresses his human side. Cue Superboy pulling off a Punch Catch and growling "My turn!"