Nothing against Mr. Kutcher of course, but I seriously question his ability to play this character. This is a serious role with serious emotions and serious responsibility, and I'm not sure if Kutcher has the resume or the ability to pull off Steve Jobs.

As justanotheratom notes, Christian Bale would probably be a much better choice. Not solely because of the fact that Bale is a far more accomplished and critically-acclaimed actor, but because he seems like he could really do well in Steve Job's role. I just can't see Ashton Kutcher in an argument with a young Bill Gates or explaining principles of design to early investors. He just hasn't proven that he's able to really own a complex character.