Rango intentionally using the film's entire Chekhov's Armoury to defeat Jake and the mayor. Not only is it just awesome incarnated, it shows he's gone from a wannabe hero lying about being one to a real hero.
The identity of The Spirit of the West.
Just the identity? Hell, that whole scene was just pure awesome.
The entire wagon chase. Bats with gatling guns? The Ride of the Valkyries played on banjos? A cross-dressing chameleon? Yes please.
Don't forget the words that started that chase. After Rango says "We've got your entire family surrounded!" The mole says "My entire family?"
And before that, even: "Reach for the sky!"
Beans has a slightly less violent one: "My daddy was NOT a BURDEN!"
"Go to Hell!"
"Where do you think I came from?"
Rango inventing the Rango persona was pretty impressive. Eating Bad Bill's cigar was also incredibly ballsy.
So, Rango's gone and brought water back to the town, tricked Jake into wasting ALL of his ammo, and has him at point-blank gunpoint with the already awesome line "It only takes one bullet." Jake (not unjustly, given their last encounter) calls Rango out and states that he doesn't have it in him to pull the trigger. Rango just glaaaaaaaares, and states, "Try me." Jake suddenly realizes this ain't the same Rango.
Jake's reaction after Rango successfully breaks out of the Bank of Dirt, knocking the Mayor on his shell and completely defusing the whole situation.
Basically, every single frame containing Jake is a CMOA for someone. Special mention goes to his introduction, which demonstrates exactly why he's The Dreaded in a scene that's as terrifying as it is awesome.
The hawk showdown, in which Rango unintentionally fuels his whole "one bullet" spiel to the people of Dirt.
About a decade after Jimmy Neutron: Boy Genius lost the first Acadamy Award for best animated feature film, Rango has become the first Nickelodeon animated movie to win.