I've always believed that if we say "no" as seldom as we can, yell very little if at all, and choose my battles wisely, it would serve me well when I do put my foot down.
This has worked very well for me. I've got 4 great kids (2 teen boys who are stepsons) and two daughters 14 & 9. I am very lax about most things, giving them a lot of freedom, but at the same time making it quite clear that I'm the boss (I don't argue or explain myself, and if they don't do what they're told there is a consequence they don't like). Yet I try to balance it with lots of fun, joking and like I said, they have a lot of freedom. Kids over constantly, no curfew on the weekends, etc.
Yesterday my daughter came to be about an issue that I felt very strongly about. She didn't like my answer and tried to argue. I explained it to her but told her I wasn't going to convince her. She didn't have to agree, just understand why. She's as stubborn as I and very beautiful, popular, etc. I felt great when she commented that it's not like me to say no and I told her that's all the more reason to respect when I DO say no that I've got to have a good reason. She actually agreed with me about that and stopped arguing. She knew that if she continued to push it there we be an outcome she disliked even more and there was no drama..
CHOOSE YOUR ARGUEMENTS WISELY! Imho :)