The director's cut version - * boom!* "...I ain't that good."
Ash cutting off his own possessed hand in the film prior to that seemed like more of a "Holy Shit!" moment. His subsequent mounting of a chainsaw to the stump can only be described as "Groovy."
"I'll swallow your soul!" "...Come get some."
Or in Evil Dead II, when he responds with "Swallow this." [Shotgun blast].
In one of the games, the bartender he was commiserating with says this, prompting Ash to borrow his sawed-off double barreled shotgun. "Make mine a double." [BLAM!]
The Deadite possessing Ash's love interest decides to taunt Ash by saying "You found me beautiful once." Without missing a beat, Ash comes back with "Honey, you got real ugly."
Ash surviving the pit. He climbs out and starts challenging everyone first in a soft voice then in his BOOMSTICK voice.
"The name's Ash." chk-chhk "Housewares."
Just prior to that: "Lady, I'm afraid I'm going to have to ask you to leave the store."
And then: "Hail to the king, baby."
In Army of Darkness, after Ash has put the Primitive Screwheads in their place, he's reclining on a couch getting fed goodies by lots of girls, and Sheila tries to get in his good graces.
Ash: First you want to kill me, then you want to kiss me... blow."
For that matter, practically every line he delivers in both movies was Rated M for Manly.
The initial defense of the castle with flaming exploding arrows. Ash said it best.
Lord Arthur's stand in Army of Darkness.
The sequence in Evil Dead II where Ash is prepping for the battle with Henrietta, getting both his chainsaw and sawed-off shotgun ready before uttering the line "Groovy," deserves special mention, since that was the exact moment the Ash we all knew and loved was born.
Evil Dead (2013)
The finale, holy crap, the finale. David's Dying Moment of Awesome to his fallen friend now turned Deadite, Mia against "The Abomination" with her tearing her own damn hand off after it was trapped, and ending with this exchange: