What Makes a Butch Woman, well, Butch?

The next Gather is approaching, and I've had a few impromptu discussions already about butch lesbians. With the news that Chastity Bono will soon be transitioning to become Chaz, it seems like it may be difficult to NOT talk about transgender men on this butch panel. It is interesting as the butch identity may arguably be the most common identity conjured when one thinks of a "lesbian," but the emergence and visibility of the transgender community may transform this thinking.

This all leads me to ask, are lesbians defined as butch based on the way they dress? How they carry themselves? Is it a state of mind? Is it a role they play with their partners? Are certain behaviors more butch than others?? OR, is a lesbian woman butch simply because she identifies herself that way??

Where to begin? How about July 12th at the LGBT Center?