Well, even though a lot of people certainly do have their own mentality of what a Christian is, the fact is that although the Bible is full of different characters, there are certain things that all Christians are to adhere too while there are also things that are just personal choice. For example, I'm in ministry so I meet and work with a lot of pastors and missionaries. One of my closest friends here won't allow musical instruments in his Church, he believes that they are a distraction and that God wants us to focus completely on Him in worship. I on the other hand really like music, and many times I like to have something really upbeat.
The Bible promotes either one, although I know most people will instantly think of Psalms and how it talks so much about praising God with instruments, there are also lots of places where silence is promoted. So that is something that would be up to the individual really.
On the other hand, things like not committing adultery, or stealing, and worshiping Jesus alone are things that any non-Christian should know is part of what we believe, therefore creating a stereo type.
That's what I think.