People that say Bruce could beat anyone are annoying. They are missing the point of why Bruce was so great.
He was not great because he was the best fighter in the world. He was great because he was a visionary. He recognized that tradition was holding back martial arts from evolving, so he broke tradition and studied multiple arts.
He also broke tradition and looked at each technique with a scientific eye. He even started referring to them as the "martial sciences" instead of martial arts. Whatever technique was effective, he kept, whatever was not, he threw out.
Thus he created the ultimate martial art: The way of no way. Which basically says, if something stops working, stop doing it, and replace it with something that does work. So MMA fighters nowadays are all practicioners of Jeet Kune Do whether they realize it or not.
The only thing you can fault him for is perhaps his testing methods. Whereas Helio and Carlos Gracie would regularly fight people in order to discern which techniques worked and which ones didn't. Bruce Lee rarely if ever tested his techniques in this manner. But you can hardly fault him for that. The man had a movie career to think about and couldn't risk getting his face bashed in or having a serious injury that would prevent him from doing his fight scenes.
So the result is that Bruce could most likely beat up most guys on the street, and likely most mcdojo masters as well. However, I firmly believe he would falter against anyone who tested themselves in real competition and had success. I think he would've lost to Chuck Norris, and Chuck has said this too, but of course he got so much hate from the fanboys that he had to backpedal on that statement.