Evan Almighty
Morgan Freeman as God? Well, why not? He has the advancing age and regal bearing and sonorous voice to be considered dignified, and possess sufficient gravitas, but he also has a sense of humor, laughs easily, and can even dance, on occasion.
Steve Carrell as Noah? Well, why not? As recently-elected Congressman Evan Baxter, he has the name recognition, organizational skills, and the personal charisma. He's lacking somewhat in the faith category, but that can be developed, because he's the kind of man who works hard, loves his family, tells the truth, can invest himself in the grandiose, and does not give up easily.