“The Curious Case of Benjmain Button,” “The Dark Knight,” “Frost/Nixon,” “Milk” and “Slumdog Millionaire” will be duking it out for the Producers Guild of America’s feature film award, given out on January 24. Snubbed in today’s PGA nominations — the beginning of the second round of awards season — were “Doubt,” “Revolutionary Road” and “The Reader.” I still think it’s likely “Doubt” will replace TDK when Oscar nominations are announced on Jan. 22, with TDK’s Christopher Nolan getting a nomination for best director in place of “Doubt” ‘s John Patrick Shanley. For Best Picture, it’s strictly between “Slumdog Millionaire,” “Benjamin Button” and “Milk.” The Director’s Guild will be announcing their nominations on Thursday morning; that night, the Broadcast Film Critics Assn. will be handing out their awards, followed by the Golden Globes on Saturday night.