Anton Chigurh blowing up a car in front of a store using a piece of torn cloth and a lighter.
The scene near the end where he gets his arm broken in a car crash and treats it as no worse than a scratch, even when a bystander points it out.
Every scene with Anton Chigurh is a mix of Crowning Moment of Awesome and Nightmare Fuel.
This is one of the few movies that starts with a Crowning Moment of Awesome, Ed Tom's voiceover speech, which so perfectly encapsulates the feel of the movie and the despair of his situation that it leaves you breathless
It's pretty impressive how long Moss was able to survive while on the run from Anton. Not only that but he was also able to wound him a few times!
A meta-example is the famous coin-toss scene in the gas station, by virtue of the great performances by Bardem and the man playing the attendant. It's unbearbly tense, and the audience is left straining at every word.
More a meta-example, but the unprecedented amount of praise and accolades being showered upon the Coens for the film, their first film to be simultaneously successful at both the box office and with critics since O Brother, Where Art Thou?. After a lull in their career and a three-year absence, they make what could possibly considered the best film of their careers, as well as finally giving them the Best Picture and Director nods they deserved.