Living in Utah as I do, you hear a lot of substitutes for common swears. A large percentage of people here, including myself, are taught that swearing that is bad or at least lame.
Most people still feel the need to use other words to fill in the void left in our life by not swearing. Basic fillers are used by the wide majority of people here and everybody knows them. Thanks to Napoleon Dynamite, you probably know them too.
As for me, I try to go beyond the norm and create new swears. My current one is “Crackers in my hat!” I got it from a friend who came up with it one day when he spilt crackers into his hat.
A common swear replacement that non creative folk use way too much in my opinion. Freakin' A.
Freakin' A. Let's think about this for a second. I've known some amazing swearers in my time, people who could, and would, string so many swears together that it becomes a language of their own. Never once have I heard one of these people use the combination that “freakin' A” stands for. When they, the swearers enter into a situation that would cause a non-swearer to say “Freakin' A” they too say “Freakin' A.”