If you don’t mind I’m going to be specific with my favorite moment in all of DC media
Justice League Unlimited EP Divided We Fall
Justice League is pretty much beaten. Braniac/Luther is about to shoot flash with a shotgun like the parallel Justice Lords world.
Braniac/Luther: “Looks like the question was right. I kill you then Armageddon, right on schedule”
Flash: “No” Takes out constructs holding him
Braniac/Luthor: “Are you going to fight me boy?”
Flash looks around turns and runs
B/L thinks he fleed then proceeds to build what he originally planned then he hears it a hypersonic sound in the distance breaking the sound barrier. He realizes its flash. He ran around the whole world and hits him before he can react
The music along with the animation when flash is running around the world accessing the full speed force hitting B/L and then defeating him is one of the most powerful moments I have ever seen in any DC media and made me a Flash fan.