Jimmy Cagney - a great actor?

Cagney won one Oscar and was nominated for a couple more, but I have never viewed him as a great actor, mainly because he was put in stereotyped roles, and that flavor always permeated his performances. No matter what role he was playing, he always seemed to be a little bit of a gangster. However, his contemporaries seem to have had a high opinion of his abilities. No less an authority than Orson Welles said that he was "maybe the greatest actor to ever appear in front of a camera."