Critics looking to explain why the beloved novel The Great Gatsby has never successfully been adapted to the screen often cite casting issues. Mia Farrow didn't quite connect as Daisy Buchanan, Gatsby's shallow but beautiful love interest, in a failed 1974 movie version, and Mira Sorvino, taking on the same role in a ponderous 2000 BBC production, fared little better. Now Oscar-nominated director Baz Luhrmann (Moulin Rouge), who's readying a new adaptation of F. Scott Fitzgerald's classic, is said to be considering just about every "gorgeous actress in her twenties with pale skin and A-list credentials" to play the pivotal role. Here's the early word on 7 contenders:

1. Rebecca Hall
When Luhrmann recently workshopped his Gatsby screenplay, Hall (The Town) read the part of Daisy, earning buzz. While Luhrmann is apparently far from decided, says Mike Fleming at Deadline, "I'm told that Hall is in the running."

2. Natalie Portman
An Oscar frontrunner for her performance in the upcoming film, Black Swan, Portman has the upper hand both "aesthetically" and "talent-wise," according to Krystal Clark at ScreenCrave.

3. Keira Knightley
Fitzgerald described Daisy's voice as being "full of money," and willowy Brit Knightley (who channeled a disaffected aristocrat in Atonement) "certainly fits that bill," says Adam Markovitz in Entertainment Weekly. "But is she too British to play such a distinctly American character?"

4. Michelle Williams
While all the actresses on the list are capable, Williams is my top pick, says Mike McLaughlin at Get the Big Picture. "She's got the physical traits to embody Daisy as well as the acting chops to back it up." Bonus: She worked well with Leonardo DiCaprio (who's been cast as Jay Gatsby) in this year's Shutter Island.

5. Blake Lively
The buxom "Gossip Girl" (one of Rebecca Hall's co-stars in The Town) fueled rumors that she was under consideration when she was seen dining with DiCaprio and Luhrmann last week. "All wrong for the part," says Dodai Stewart at Jezebel. Despite her "Gossip Girl" experience, "[Lively] lacks the bon vivant effortless snobbery and casual hauteur of the terribly rich."

6. Scarlett Johansson
The actress reportedly auditioned for Luhrmann at a digital film studio in New York last week, and has said she was "very happy" with how it went. "Perfect," says Tom DiChiara at "She has the mix of grace and hidden passion to play a spot-on Daisy Buchanan."

7. Amanda Seyfried
Seyfried (Mamma Mia!) has "got a great mix of innocence and knowing," says Stewart at Jezebel, who's surprised that certain other names aren't being floated. British actress Carey Mulligan (An Education), for instance, also has the requisite "childlike aura."