What's the coolest sword in the entire universe?

Anyone can wave around a phaser or a blaster — but a sword is a truly elegant weapon, a product of a more civilized age when you had to slice someone to pieces at close quarters. But what's the coolest fictional sword of all time?

Please include a picture of the noble blade you're recommending. Or maybe a cool video of swordplay. Thanks!

Top image: Excalibur by Coco1994 on Deviant Art