What should I do if I have a good job but not a burning professional ambition?

I have a good job that pays well. I perform my job well to the best of my ability. But I don't feel about it the same way that Howard Roark felt about the field of architecture in "The Fountainhead" or that Dagny felt about the railroad business in "Atlas Shrugged". I don't hate my job -- I do enjoy the work and the people I work with. But it's not my burning passion. On a scale of 1-to-10, my paying job (and the overall field) is a 7, but I also have various non-paying outside hobbies and activities that are more of a 8 or 9 for me. Should I try to cultivate a strong passion for my paying job? Or look for a different line of work? Or ramp up my pursuit of various hobbies and outside activities that give my greater satisfaction on the side?