Like Holmes and Watson, Downey and Giamatti are roughly the same age. Clearly, it doesn't matter that we have an American Holmes, so an American Watson shouldn't be a big deal, either.

Also, I think he can play off Downey very well - both are incredibly bright, distinctive actors who have a tremendous natural sense of humor in their performances - and he could play the part whether it takes place in the 19th Century or the 21st.

Unfortunately for the rest of the guys on this list, Giamatti was the first actor who popped into my head. It'll be very hard for me to think someone else might be a better fit.

2 - Jim Broadbent

Older, yes, and British, but what I love about this choice is what a natural supporting actor Broadbent is. He almost never takes a direct hit of cinematic sunlight; he's always in someone else's background.

That's not to say he's not a capable actor. I mean, watch just about anything he's ever done. He's just a very solid choice to support a dominant personality in a film, and you know what you'll get with him every time.

Works very well if they keep this film in the Victorian Era, too.

3 - Eddie Izzard

Think of it: Two guys who have played Charlie Chaplin in films - both of them quite well - joining forces as Holmes and Watson.

Izzard is as good an actor as he is a stand-up comedian (and I once saw him perform live for well over two hours), and he brings an assured intelligence to the role of Watson, maybe a tad more intelligence than the character himself ever gets.

More a fanciful pick than the other two, but it would be great to see.

4 - Chiwetel Ejiofor

If they're thinking outside the box, and I believe casting Robert Downey Jr. and hiring Guy Ritchie for a Sherlock Holmes movie is definitely outside the box, then who better than Ejiofor? He's a brilliant actor, needs more press, and he can absolutely hold his own with Downey. In fact, if we think Downey's a better actor, it's only because we've seen more of his performances. This guy is the truth.

If they bring the story forward a bit chronologically, what in the world would be wrong with a black Watson? I think it has about as much chance of happening as selling this house I bought last year for a significant profit sometime in the next few months, but when you have two characters as closely aligned as Holmes and Watson, why not cast accordingly? They'd make a great team.

5 - Brendan Gleeson

You don't look at Brendan Gleeson and see the whole story, which is strange because when you look at Brendan Gleeson you see a hulk of a man with tons of mileage. Holmes and Watson met after Watson's medical discharge from military service, and I can see those kinds of echoes in Gleeson's eyes.

He's been an extremely versatile actor - love him in Potter, Dark Blue, and In Bruges over the past few years - and physically, I think he's probably the best choice if they're sticking to the story somewhat.

And, because Holmes is the star and Watson is more the bedrock, Gleeson can fill the role the same way Broadbent can, effectively and without marching on Robert Downey's spotlight.

6 - Alan Rickman

For almost any other role in the world, Alan Rickman would be much, much higher on the list. The only reason I have him here is because he simply can't escape being too hip for the room. He's always above the fray, with snide remarks and uncontrollable sarcasm. That's why I love his work.

However, that's not what John Watson's all about. And I think there's a tendency with Rickman to be a little more dominant when he's on screen than this character allows for.

I'd love to see the screen test, don't get me wrong - and who knows, maybe Watson's personality will be changed in the story along with so many other things - but Rickman would be a real dark horse.

7 - Bill Nighy

Old (but three years younger than Rickman and Broadbent), distinguished, wry, subtle...in a way, that's Dr. Watson. But like a few other candidates, he's not physically the best match. He'd probably make a better Holmes, when you think about it.

I actually just like nominating Bill Nighy for any part that comes up. Tim Burton's Alice in Wonderland: Bill Nighy. Captain America: Bill Nighy. It's fun to pretend.

What I do like about him as a possible choice, though, is his ability to do a lot without saying very much. He's one of the best bemused, quiet actors working today.