Marvel:
Captain America- Phenomenal hero, great strength, awesome backstory, American Hero.
Spiderman- He's a webslinging son of a gun who gets called Tiger by a redhead model/actress/many more.
Iron Man- I honestly don't need to explain this.
DC:
Batman- Batman is the true hero everyone can possibly be. He has no powers, simply skill. Comes from a sad backstory, he's a playboy millionaire, and he raises 3 sons, and currently is raising a 4th! Also Turo.
Nightwing- Nightwing doesn't get a lot of credit, but he may quite possibly give Batman a run for his money. Nightwing is **** Grayson (The first Robin) Grown up, he's the World's Greatest Acrobat, he's got wingdings, and his electrified Escrima sticks make him all the better! He even can ricochet with accuracy! Nightwing is one of my favorite comic book heroes of all time. Also, he gets all the ladies. Google Nightwing and on image search and see what pops up.
Superman- because: [video=youtube;zwoXARqonns]http://www.youtube.com/watch?v=zwoXARqonns[/video]
Also Green Lantern, and the justice league are close as well.
Villains:
Joker- DUH.
Riddler- His intellect is vastly superior, he has a crazy mind, and poses quite the threat mentally. Jim Carrey made him look like crap in the film.