Edit: Damn, rush you beat me to it.....
chops have the same basic philosophy behind them as cafe's, take a stocker and make it uniquely yours.
My only problem with Chops now is that they've become mainstream, and have lost a huge chunk of the individuality that made them CHOPS. the same area that cafe's are heading into now
I think these are 2 opposite schools of thought.
Cafe's are the poor mans race bikes. Their look has a purpose, unlike choppers. They're spartan in appearance to save weight. Usually the owners tinker with the mill to make it faster, and a brakes and suspension are almost always upgraded in some sort, ducts on drums, cross drilled rotors, speed holes everywhere. All these things serve a purpose. Go fast, stop fast, turn fast. the ultimate in function over form.
Choppers, like you said are art. They are a pure expresion of the owner.
Nothing wrong with that.
I like my chopper's with that old school flavor to them. I don't really care for the modern styled chops. I don't know what it is, but once everything gets covered up and is over stylized it loses "soul" for a lack of a better word.
There's this bike called El Peligroso, I think was on biker buildoff and it's totally bad ass in the detail department. All hand hammered sh!t. This is my idea of how a chop should be.