I regard curses as just words, but words that should be saved for extreme circumstances. I curse only when I'm extremely mad or frustrated, and if I do, my friends know mostly to back off and back off now. I've found that if you curse too much, people never take you seriously anymore.
When I'm joking around with my friends, I'll beep or silence the curse words (like on an edited TV show). Usually, the most extreme that I get is "Crap", "Dammit", "Fricking", and "Shoot". I really should cut down on the "My God"s, though. I know some people are offended by that.
When I'm to myself, I'll say some of the more vulgar ones to myself or think it in my head. I use those around my parents sometimes as a joke or when I'm telling a story, and they never mind, especially since they know that I'm not one to use them often.
I make it a habit never to curse in front of little kids (I have a couple of cousins that I'd never want set a bad example for), and adults that you've just met. I don't really care if anyone else curses, just as long as they do it out of hearing range of kids. When people throw in a swear every other sentence or use it in an very detrimental way, however (example: the N-word), I either start taking them less seriously or start tuning them out altogether.