There was a time when the most highly acclaimed actor you could get to star in a movie based on a Marvel comic was Dolph Lundgren. But now, as both the budgets and the respectability of "comic book movies" have increased, it's become standard practice for Academy Award winners and nominees to appear in them.
Currently, four out of the 20 Oscar nominees in the acting categories will be in a Marvel Comics film in the next two years.
Check out the article on Yahoo about Oscar-quality talent appearing on comic book adaptations: