Previous Favorite Costumes: Jack Knight - Red Tornado - Jeff Smax - Adam Strange - Deadshot - Blue Beetle - Alan Scott - Mister Miracle - The Creeper - Dr. Strange - Dr. Doom - Iron Man
Zoom. I like the idea of making a villain's outfit the polar opposite of the hero he's meant to fight. The easiest way to do that is to pull a palette swap, which is also the quickest way to create legions of faceless goons to beat up in side-scrolling video games.
Green Goblin did something similar. Spider-Man's red and blue, so Norman, in his madness, knew that purple and green was the obvious opposite number. Same with Superman's red and blue getting matched up with Luthor's stupid power suit's purple and green. Batman's cape's blue, Joker's coat is purple. You take one look and you know who the bad guy is. Especially because good guys almost never wear purple.
Seriously, I'm struggling to come up with a hero in purple.
But when the Flash needed a nemesis, they gave him a man in an honest-to-God pallette swapped number. Whereas Flash was red with yellow details, the creatively named Reverse-Flash is yellow with red details, just like how the Flash is good and the Reverse-Flash is evil. Now, this could've just as easily been Eobard Thawne, AKA Professor Zoom (which is, I have to say, the best alias ever. I would so take any course a Professor Zoom taught) AKA the original Reverse-Flash, but the newer Zoom has the current Flash's pointy-lightning belt and slightly-less-doofy ear-thingies, so he wins. Besides, this Zoom has super creepy little red eyes.
Honorable Mention: The Flash. Wally West, though, because, as previously stated, I like his belt better.