Rich, this is a big topic that many are trying to understand. If this is not the direction you would like this thread to go, let me know and we can disregard.
It is one of three marks of a "true church" that John Calvin identified (though indirectly):
1) right teaching of God's Word
2) right administration of the Sacraments
3) church discipline
If you would like this thread to open this topic up for general discussion, we might discuss:
1) What is church discipline (e.g. Is it negative? positive? both?)
2) What are the forms of it
3) How practically is it administered
4) How does it relate to church membership, leaving a particular church, etc.
5) What are general differences between reformed churches and broadly evangelical ones in this aspect?