Roman Sinner Remix

It's not hard to look around and see people who have made mistakes and continue to make mistakes.  While no human is perfect, what does God actually expect from those who claim to know Him?  Do we have to be perfect?  It seems to me that if you attend church enough or spend time with enough Christians that you will be smothered with the phrase "WE ARE ALL SINNERS."  Is this true?  Is there a way to be perfect in the eyes of God or are we all sinners no matter what?  What does the bible say?