Took a while to figure this out. I'm proud of the results, and hope that you will be as well.
1. Superman - Spencer Conway
Can you give me a reason this guy shouldn't be Superman?
"Well, he may not be fit enough for it!", you say? Funny that, because I could have sworn that Christopher Reeve was playing a sunken-chested asthmatic before he got the job as Superman. A little time and a personal trainer later, and... well, you know the rest. This fellow, a Portland actor of little notoriety, has a defining characteristic of "looking like Superman". I think he'll do fine.
2. Batman - Michael Fassbender
He's already a fan favorite, and it's obvious why. His only real flaw is that his hair's too light -- and hair can be dyed. He's in great shape, good looking, and a superb actor. In 300 we see him do action scenes (also means he's undergone the infamous "spartan training"), in Inglourious Basterds we see that he can be suave and debonair, easily sufficient to be a perfect Bruce Wayne, and over his career it's clear that he can pull of the intensity of Batman. Give him a voice coach to work on his american accent a little and he'll be golden.
3. Wonder Woman - Bridget Regan
Huh. Nope, I don't see a Wonder Woman there.
"Okay, Joygirl, maybe she looks the part. Can she act it?"
I've said my piece.
4. Green Lantern - Jensen Ackles
This one took me a while, and I finally came to Jensen, best known as the boyish and brooding Dean Winchester on the show "Supernatural". He has the perfect blend of cockiness and glaring intensity, he's in perfect physical condition, and he's proven over time that he's a darn good actor.
5. Flash - Bradley Cooper
Another fan favorite, he's funny, good-looking, in good shape, and a damn snappy dresser. Could play Barry or Wally, should he desire, he could easily be comic relief while still being believable.
6. Aquaman - Matthew McConaughey
HAH. I bet you were thinking I mean pretty-boy, slippery-when-wet McConaughey? Nope. In the movie Reign of Fire he showed a few little-known traits:
1) If he puts his Game Face on, he suddenly doesn't look as goofy anymore.
2) He can grow a pretty awesome beard.
3) He's physically intimidating
4) His voice isn't always silly. It can be scary too.
We already know that he does well with water, so he seems like an excellent choice for a more barbaric, bearded, harpoon-handed "King of Seven Oceans" type Aquaman.
7. Martian Manhunter - Arnold Vosloo
ZOMG. A non-black Manhunter? Blasphemy!
If it makes you feel any better, he's technically south african. So... yup.
Anyway, he's perfect. His voice is low and implacably exotic, and his features are similarly lumpy and alien. Paint him green and I think you'll be pleased.
8. Hawkman - Gerard Butler
Another fan favorite. I wonder why. Gerard Butler would like you to know: "Rawr."
9. Green Arrow - Ben Foster
Thanks for checking out my list, folks! Hope you enjoy it!