Lol IADad, I have heard "SHUT THE FRONT DOOR!" before too, one of my favorites. Another one we had in school that we liked to use to put people on edge was "YOU GOD DAAA - NDY BLUE EYES!!" lol. Dumb, I know, but hey you know how it is.
DH has always been a real potty mouth, his whole family on both sides are so much so that they make me feel uncomfortable all the time lol! I swear too, don't get me wrong, but these people are just R-Rated! I wont tolerate that kind of thing around my kid though, at least not to that extent, but I'm honestly not completely crazy about it either. DH and I have really cleaned up quite a bit since DS was born. We rarely let a swear word slip around him, and I think that the ones we do let go of don't phase him at all. I think because we don't use them all the time, he realizes that they are not regular words to use and they don't stick in his mind as well as regular words. There have been a couple of times that he had innocently repeated one, and we just told him "Hey, don't say that. That's not a nice word." And that always seemed to be enough for him. I don't want him to think he can swear by any means, but I also don't want him thinking that swear words don't exist or that people don't use them. I think that makes them too mysterious and like a special thing to kids when they finally do hear them. Plus I have to teach him about them in some moderation thanks to the potty mouth family members. -sigh- :/ They tone it down around him to be polite thankfully (mostly because they know I'll say something to them if they don't), but they certainly don't completely censor themselves so it is how it is. I can't control other people, but I can control the way my son views what other people do to an extent.
I would say that we tend to use replacements a lot, like freakin, friggin, dang it/darn it, common stuff like that. Where I can't deny the argument that you might as well say the word, I think they are a lot more harmless than the actual words themselves if you feel the need to say something haha.
What I HATE, is when parents just cuss all out whenever they feel like it all the time in front of their kids and then yell at them for repeating it. Its like, ummm DUH??? You shouldn't be mad at your kids for that, you should be mad at yourself.