The nominees are:

George Clooney, Michael Clayton
Daniel Day Lewis, There Will Be Blood
Johnny Depp, Sweeney Todd
Tommy Lee Jones, In the Valley of Elah
Viggo Mortensen, Eastern Promises

Man, this is a pretty strong group of actors. Clooney and Jones, though, in my mind stole spots from James McAvoy (Atonement) and the aforementioned Emile Hirsch (yeah, I'm not letting it go). But it probably doesn't matter, because Day-Lewis has this one in the bag. He was so good in 'There Will Be Blood' that his character shows up in my dreams, uninvited. And he's usually saying "There's an OCEAN of OIL underneath our feet!" My other favorite in this category is Viggo. Ahh, Viggo. What a role. What a film (that also deserves a few more nods, if ya ask me). What a buck-nekkid fight scene ...