Since it's a reboot, I decided a complete cast overhaul was needed. Admittedly, Chris Evans and Michael Chiklis were good, but let's try something new.
Reed Richards/Mr. Fantastic: Alexis Denisof. He's proven he's a good actor and excels at being brainy.
Susan Storm-Richards/Invisible Woman: Elisabeth Rohm. Seriously, WTF was the studio thinking when they cast Jessica Alba? Rohm on the other hand has proven in her many TV roles that she actually is talented, and actually looks like Sue too. No bad dye jobs or make-up here!
Johnny Storm/Human Torch: Kellan Lutz. Yeah, yeah, I know, he was also in the Twilight movies, but he's definitely got that cheeky sense of humor and attitude for Johnny. And he and Elisabeth Rohm actually can look like a brother and sister pair.
Ben Grimm/Thing: Aaron Douglas. He is best known for his role as Galen Tyrol on Battlestar Galactica, and aside from being a pretty big guy, he's also good at playing tormented but strong too.
Now for the villains...
Victor Von Doom/Dr. Doom: Richard Armitage. He's already got the sharp European features (since Doom is Latverian), and is a total dead ringer for pre-scarred/masked Victor too.
Mole Man: Wayne Knight. C'mon, do I have to explain this one?
Namor the Sub-Mariner: Dominic Purcell. I know, Namor's not really a villain (more of an anti-hero mostly). But Purcell is definitely buff enough and proven himself a good actor.
And one side character...
Alicia Masters: Vera Farmiga. She's been making her name in several movies, and is really genuinely talented. And she's beautiful (in a unique sort of way) as well.