Brad Pitt- Cost too much....marvel will NEVER pay him what he would want to star in thor.....PLUS he would shoot the budget up for the avengers tremendously.
Gerard Butler- Will do another prequel to 300 in the next 6-9mths so that writes him out of the equation. He's gonna go for the BIG CHECK...which he deserves...
I say go with Kevin Mckidd from rome/trainspotting/journeyman/grey's anatomy (this season)....he's proven he has better acting chops than most of the unknowns mentioned. He can play the Dr. Blake character well, of course he can buff up for the thor part. I think he's 5'10, but with boots/lifts he easily can look 6'3 on camera...
Come to think of it...ROME was pre-asgardian training...lol...
You guys REALLY need to stop throwing out names of guys who have NOT proven they can act and have NOT carried a BIG BUDGET movie or ANY movie that has made a profit yet....hell most of the NEW names on here DONT have anything major coming out over the next 5-7mths. Marvel will make a decision by March of next year at the latest...hopefully...lol.