I post on many sites:
JC, Organissimo, AAJ, I hate music, Good Music Guide (classical music), freejazz.com, bagatellen, the aebersold forum, sax on the web, I love music, etc.
They are all the same. There can be flameouts on any board. And yes, on other subjects it can get much much worse. Believe it or not I have seen much worse all out war on plant forums (I used to frequent plant listservers when I worked as a botanists). For some reason jazz people tend to be more polite than plant freaks. Go figure.
As it stands now, jazz corner and organissimo match my interests the best.