But CBS News The Early Show Entertainment Contributor Jess Cagle is not surprised by Ledger's nomination. "He has gotten a consensus of critical awards so far," Cagle said.
"Brokeback Mountain" also appears on the of the year.
"Right now 'Brokeback Mountain' really is the movie to beat," Cagle added.
Other best drama picture contenders were the murder thriller "The Constant Gardener," the Edward R. Murrow tale "Good Night, and Good Luck," the mobster story "A History of Violence," and the infidelity drama "Match Point."
"Good Night" was produced and directed by George Clooney, who was also nominated for the supporting actor award for "Syriana."
"It is really a step toward him becoming a director which is what I think he really wants to do with his life from now on," said Cagle.
The Globes have a separate category for musical or comedy films. Nominated there were the theater tale "Mrs. Henderson Presents," the Jane Austen costume pageant "Pride & Prejudice," the Broadway musical "The Producers," the divorce story "The Squid and the Whale," and the Johnny Cash film biography "Walk the Line."
Along with Ledger, who plays a family man concealing a homosexual affair from his family, best dramatic actor nominees included three actors playing real-life figures: Russell Crowe as Depression-era boxer Jim Braddock in "Cinderella Man," Philip Seymour Hoffman as author Truman Capote in "Capote," and David Strathairn as newsman Murrow in "Good Night, and Good Luck." The fifth nominee was Terrence Howard as a small-time pimp-turned-rap singer in "Hustle & Flow."
"The two actors who are neck-and-neck for the best actor race are Heath Ledger and Philip Seymour Hoffman," said Cagle.
Felicity Huffman received two nominations, best dramatic actress in a film for her role as a man preparing for sex-change surgery in "Transamerica" and best actress in a TV musical or comedy for "Desperate Housewives." Her "Desperate Housewives" co-stars Marcia Cross, Teri Hatcher and Eva Longoria also were nominated.
Other best dramatic film actress nominees were Maria Bello as a wife learning painful secrets about her husband in "A History of Violence," Gwyneth Paltrow as an unstable math genius' daughter in "Proof," Charlize Theron as a woman leading a sexual harassment lawsuit in "North Country" and Ziyi Zhang as a poor girl who becomes the belle of Japan's geisha houses in "Memoirs of a Geisha."