Depends on the company, really. When I'm with my friends, I tend to use profanity rather freely. When I'm in the presence of my mother (and, to an extent, my old man), teachers, other authority figures, and people who I'm not well aquainted with, I don't use any colorful language.
I use hell and damn regularly, but I don't really know anyone, other than my grandmother, who is really offended by those words. I wouldn't say I make excessive use of profanity in any environment, though.
Besides, profane language is so incredibly versatile. I believe it was Bill Bryson who said that the f-word is the most versatile word in the English language. He has a book about the English language in which he details many of the different meanings of the word. He also traces the history of the word [img]/xxx.gif[/img][img]/xxx.gif[/img][img]/xxx.gif[/img][img]/xxx.gif[/img].