Believe it or not, James Cameron may not be King of the World by the end of the long Christmas weekend.

His 3D sensation 'Avatar' is not losing steam -- in fact, it set nonsummer weekday box office records Monday and Tuesday -- but early estimates from Wednesday show that 'Alvin and the Chipmunks: The Squeakuel' was out-performing the Na'Vis in ticket sales, $19 million to $16 million.

And when 'Sherlock Holmes,' Guy Ritchie's action-packed addition to the Holmes movie canon, opens wide Christmas Day, there may be three pictures running in a pack for the box office lead. Early reviews of 'Sherlock Holmes' have been mixed, but even the negative ones agree that Ritchie has concocted a brand new vibe for the Baker Street team of Holmes (Robert Downey Jr.) and Dr. Watson (Jude Law). And in a market where 'Avatar' is the dominant choice for adults and 'Alvin and the Chipmunks' the dominant choice for toddlers-in-tow families, 'Sherlock' is a sure thing for teenagers. Believe it or not, James Cameron may not be King of the World by the end of the long Christmas weekend.

His 3D sensation 'Avatar' is not losing steam -- in fact, it set nonsummer weekday box office records Monday and Tuesday -- but early estimates from Wednesday show that 'Alvin and the Chipmunks: The Squeakuel' was out-performing the Na'Vis in ticket sales, $19 million to $16 million.

And when 'Sherlock Holmes,' Guy Ritchie's action-packed addition to the Holmes movie canon, opens wide Christmas Day, there may be three pictures running in a pack for the box office lead. Early reviews of 'Sherlock Holmes' have been mixed, but even the negative ones agree that Ritchie has concocted a brand new vibe for the Baker Street team of Holmes (Robert Downey Jr.) and Dr. Watson (Jude Law). And in a market where 'Avatar' is the dominant choice for adults and 'Alvin and the Chipmunks' the dominant choice for toddlers-in-tow families, 'Sherlock' is a sure thing for teenagers.

In my forecast, I'm sticking with 'Avatar.' It is the 'must-see' movie of the season, if not the year and the decade, and it is that rare blockbuster equally appreciated by critics and paying customers. The theater exit polling firm Cinemascore reports that 'Avatar' viewers are giving it a solid A grade, with 92 percent of them promising to recommend it to others. It has also become the late favorite in the Oscar race, with a buzz that will accompany it all the way to Spring.

Clearly, Cameron has crafted another juggernaut, if not as big as 'Titanic,' titanic enough. Look for 'Avatar' to do between $80 million and $85 million over the five-day Christmas holiday.

'Alvin and the Chipmunks' had a $44 million opening weekend in the middle of December 2007, and went on to a $217 million domestic gross. Talk about storing your nuts. The sequel has some competition from a pair of holdover Disney family movies -- 'The Princess and the Frog'and 'A Christmas Carol' -- but they won't slow it down much on this, probably the biggest weekend of the year. I expect the 'munks to rule to a final tune of about $60 million.

It's harder to get a fix on the want-to-see of 'Sherlock Holmes.' Ritchie's name is no guarantee. The only profitable venture the British director ever undertook was his marriage to Madonna, which netted him about $100 million in a court-ordered settlement. And though the Baker Street detective has been portrayed in more than 200 movies, the last English-language feature we saw him in was Barry Levinson's 1985 'Young Sherlock Holmes,' and it was a box office dud.

But Richie's version puts the accent on action rather than deductive reasoning and Downey and Law represent a major energy boost over the Basil Rathbone/Nigel Bruce model. Teenage boys and young adult men are going to line up big-time, spending as much as $50 million-55 million on tickets over weekend.

Also new in 2,800 theaters beginning Christmas Day is Nancy Meyers' romantic comedy 'It's Complicated,' which stars Meryl Streep as a divorcee being courted by a funny-looking new fellow (Steve Martin) and her overly familiar ex (Alec Baldwin). Meyers' last film, 'The Holiday,' had a lackluster December opening three years ago, but she has a hotter cast for this one and the trailers have been terrific. Look for Meryl and the boys to take in about $16 million over the three-day weekend.

'Up in the Air,' the George Clooney comedy drama considered by many as the movie to beat for the Oscar, expands from 175 to about 1,800 theaters. It's in 1,000 fewer theaters than 'It's Complicated,' but it went wide on Wednesday, getting a two-day head start. I expect the two films to be neck-and-neck for fourth place on the weekend chart.

The last newcomer to theaters is Rob Marshall's musical 'Nine,' which expands Friday into about 1,500 theaters. Despite an all-star cast that includes Daniel Day-Lewis, Penelope Cruz, Nicole Kidman and Kate Hudson, early reviews have cast a pall over it and a very tough field of competitors will likely keep its weekend take below $8 million.

Here's how the Top 10 look:

1. 'Avatar,' $80 million-$85 million.
2. 'Alvin and the Chipmunks: The Squeakuel,' $60 million.
3. 'Sherlock Holmes,' $50 million.
4. 'It's Complicated,' $16 million-$18 million.
5. 'Up in the Air,' $16 million-$18 million.
6. 'The Princess and the Frog,' $14 million.
7.'The Blind Side,' $11 million.
8. 'Nine,' $7 million-$8 million.
9. 'New Moon,' $4 million.
10. 'Did You Hear About the Morgans?' $3.5 million.