Rome: work or leisure?

This July I will be moving back to Rome after 26 years. During all these years I lived in many foreign countries, but mainly in the US.
As many Americans, I have an entrepreneurial mind, many ideas and lots of enthusiasm, however I am wondering if my expectations are realistic.
Is Rome a place where to live leisurely or a true cosmopolitan place where it is possible to accomplish your professional goals?
Would you tell me a little bit about your experiences?
It would really help!
Thank you.
Ciao.