I think it will go like this:
1.Boyle
2.Fincher
3.Van Sant
4.Nolan
5.Howard*

*I think if someone is going to miss out, it'll be Howard. A possible replacement I see that could surprise everyone is Andrew Stanton. My wild theory: The Academy will try and find a place in the MAJOR races for Wall-E. As much as people are talking about how the Academy won't hear the end of it should TDK be snubbed in major categories, I believe the same applies for Wall-E. An Academy award for animation coupled with a screenplay and technical awards nominations are in the bag which mirrors what Ratatouille and Nemo did. However, I think there's enough groundswell of support that the Academy will go further, and that will be either Best Picture or Best Director. No animated film director has ever garnered a directing nomination, and outside of the best picture nominations, the best director nominations arguably sends the next strongest message.

@Tobey: Very good call Tobey and I am pissed I forgot to add him to the list of possibilities. I don't personally think he will be nominated, but he is worth the mention.

Where is Andrew Stanton?

Fincher and Boyle are the only ones I'd put any money on. Aside from that, my guess is that the other three will be Nolan, Gus Van Sant, and Aronofsky (or potentially Howard). I don't know why, but I have a feeling the Wrestler may win more things than you give it credit for.

As for the actual winner? I'm very unsure. While I'm quite confident Slumdog will win best picture, the director race is more complicated. I do believe the Academy will want to honor Fincher now; after all, consider his fan following, reputation, and history of snubs. Now, Danny Boyle applies to that too, but I think Fincher has a generally larger following and reputation, which may end up giving him the win.

Which leaves me wondering: Why the hell can't the Academy give awards to the actual best movies instead of politicizing and making up for snubs? Life will be easier that way.

Boyle will end up taking the award, but Fincher and Demme are locks for nominations.

Fincher looses for the shot at the end of the movie when water floods the basement of the hospital and we see the backwards clock and the movie asks the question "What if we could turn back the clock on katrina too?" Absolute bullocks.

Gotta admit, I'm torn between Clint Eastwood (Gran Torino) & Sam Mendes (Revolutionary Road) as most deserving of this award. These are also my picks for Best Picture – they were the two films that moved me the most this year.

Gus Van Sant (Milk)
David Fincher (The Curious Case of Benjamin Button)
Danny Boyle (Slumdog Millionaire)
Ron Howard (Frost/Nixon)
and maybe Sam Mendes (Revolutionary Road)

My bet is on Nolan. The academy will recognize how he turned the comic book genre in another level. He was also the first director to ever use Imax cameras and flip a live truck over. He wanted to try new things for his film.
I hope the academy recognizes what a great film he made.
Best picture , I doubt it will win but i'd love to see a nomination. Ledger willl most probably win and director of photography and other nominations as well.
The academy is most probably not going to have Nolan win though , too bad.

I chose other I think the Changeling is really not getting the chops it deserves

I agree with Ethan. I think that The Wrestler will be up for more than people think and that it could win.

I chose other – Woody Allen for Vicky Cristina Barcelona.
For me, the story was nothing incredible, but the film was incredibly beautiful to watch. Woody Allen has such a distinct style, which I dont usually enoy but thought it was very well matched to this film.