I'm a huge Batman fan, so naturally I put more thought into casting him.
This is my cast:
Superman
-Alexander Skarsgaard: with more muscle and dyed hair (unless they decide to use MOS to set up the JLA movie)
Batman
Fassbender and Hardy are perfect for this role, but obviously they're unlikely to get it. Joe Manganiello recently expressed interest in the role, but I think that he is better suited as Hawkman or Bane or whatever.
-Logan Marshall Green: He's an intense actor, who's name you'll obviously see more often after starring in Prometheus
-Garrett Hedlund: He's a great actor, just watch Death Sentence
-Shane West: Great actor, who happens to have a voice simmilar to Kevin Conroys
-Luke Evans: Great actor, who's been suggested like a million times on here (for a good reason). He'd have to bulk up like hell though
-Desmond Harrington: He plays Quinn on Dexter, and he appeared in TDKR.
Wonder Woman
-Charlotte Riley: She was great in The Take and Wuthering Heights, with her husband Tom Hardy. She'll obviously have to put on some weight.
-Berenice
Marlohe: She looks the part, but I'll have to wait to see Skyfall to make up my mind
-Gemma Arterton
The Flash
-Joel Kinnaman
: He's a great up and coming actor.
-Lee Pace: If he isn't going to be used as Ray Palmer, he should be cast in this role. The guys a great actor...
Aquaman
-Joe Edgerton: Another great up and comer, who would play the scruffy Aquaman to perfection. Hell, I even considered him for Batman
Green Lantern (Hal)
-Chris Pine: Do I need to explain myself?
-Channing Tatum: I know if going to get pissed on for this, but he's acting has gotten better, I think...
Martian Manhunter:
-Anthony Mackie or Benedict Cumberbatch: Honestly, both of these guys are great actors. If Mackie isn't accepted as MM, he should be cast as John Stewart
Green Arrow (the goatee is crucial)
-Charlie Hunnam: I actually considered this guy for Batman. He's also an up and coming actor, who's a great actor (you'll know this if you've watched SOA)
-Travis Fimmel: He was great in The Beast. He's next going to be seen alongside Gabriel Byrne in some viking tv show
I'm still thinking about who to cast as Black Canary,
both the Hawks etc...
Sorry for not putting up pictures, I'm using my phone...