Designer Tom Ford recently posted five guidelines on being a modern gentleman. I have to say that he pretty much is spot on in my view.
Depending on the circumstances, I might bend rule no. 5 (no shorts in the city), esp. if one is in the city and going to the gym or playing a game of tennis. But everything else I wholeheartedly agree with - the emphasis on manners, self-application (i.e. work) and, perhaps most importantly, presenting oneself well as a sign of respect (not as self-indulgence).