For me, the character of James Bond lost credibility when they went out of their way to show that he wasn’t a smoker (I think it was Tomorrow Never Dies.). Screw it, I’ll just read the novels by Ian Fleming from now on!
Even the coolest Bond, (Sean Connery type), needs to show a hint of something in there, and smoking is the perfect imperfection to convey a hint of the personality of the man living that lifestyle of violence and death and risk, no matter how controlled and composed that he appears on the surface.
They would have lost credibilty with me if Bond were a smoker and he didn't collapse gasping for air everytime he had to chase or fight somebody.