Krypton:
Jor-El - Jim Cavaziel: He is a huge fan of the character and campaigned for the role of Superman in the Singer days. I'm sure he'd love to have a role in the movie, even a glorified cameo like Jor-El.
Lara - Teri Hatcher: She is a decent enough actress to do what would be needed for this role. Plus it would be a fun cameo.
Brainiac (voice) - Hugo Weaving: His voice has that robotic, but dominating and all knowing nature that such a role would need.
General Zod - Jude Law: I know a lot of people hate the idea of Zod in a Superman movie again but I think it would make a cool cameo and open up some sequel potential. Darkseid is too far out there for film, IMO. He is like Apocolypse. Sure, he is a great villain in comics and cartoons but would be ridiculous on film. Braniac is a must for Superman 2, but Zod would make the perfect end to a trilogy IMO.
Smallville:
Pa Kent - Tom Berenger: Great actor, is the right age and look for the role. Plus who plays the average, everyman better than Berenger? And that is essentially what Pa should be. The average guy with a not so average son.
Ma Kent - Jean Smart: I know she is mostly known for her comedic work but 24 displayed that she can do drama, and how! Plus, I am so sick of the fragile old woman cliche in super hero movies. Smart is nearing 60, so she is older, but not the geriatric as we are used to. She is strong willed enough that it is believable that she could muscle Pa into taking in an orphan who just crashed in a space ship plus she can do warm and caring well enough that we could see her as a stable support structure for Clark.
Lana Lang - Alyson Hannigan: I don't think Lana should be a super model quality actress. Yes, she is drawn that way, but what woman in a comic book isn't? I like Lana as a sharp contrast to Lois. More reserved and rational, more pretty than sexy, kind of the girl next door type and Alyson Hannigan fits that to a T.
Pete Ross - Tom Welling: Just to see the reaction on the web.

But seriously, Pete wouldn't have a role in my ideal Superman movie. The Smallville scenes should focus on Clark's relationship to his parents and Lana. Throw Pete in there and you are adding too much. Besides, Pete's overly important role in Superman mythoes has always felt forced to me. Vice-president and later president? Really?
Metropolis:
Lois Lane - Sarah Lancaster: I don't really have a good reason for this other than the fact that she has a GREAT look for the role and is a fairly good actress. But beyond that, its impossible to cast Lois without first seeing how she and the Superman actor play off one another. And again, tell me this isn't a good look for Lois.
Lex Luthor - Jason Isaacs: I need a reason aside from the fact that he would be absolutely orgasmic in this role?
Perry White - Christopher Walken: I think this is a role Walken would have a lot of fun with and the results would be amazing.
Jimmy Olsen - Kevin Connolly: I hate "cub reporter Jimmy Olsen." Jimmy shouldn't be a kid, he shouldn't even be a teenager. Its ridiculous to think that the equivilant of the New York Times would hire a child or teen to take photos for them. At the same time, Jimmy should essentially be a rookie photographer who Perry uses as more of an errand boy. Kind of the Lois and Clark portrayal. Kevin Connolly would fit this well. Young, eager and ambitious, but also a good friend to Lois and Clark.
John Corbin/Metallo - Viggo Mortenson: Great actor. I feel he would capture the tragedy of Metallo and his motivations perfectly. No one wants Metallo to be some two dimensional villain. He has to be a man, albeit a criminal who was transformed into a monster. Mortenson would capture this well, I think.