That brings up another interesting point in where to draw the line- just listening to music against buying it; for instance, I listen to some Skrewdriver (and some Buju Banton)- but it's music I've downloaded (without paying). I definitely would NOT buy ANY Skrewdriver albums (even their pre-racist material) because I know that my money would go to people or groups who may use that money to further advance their ideology.
Skrewdriver is kind of a bad example though, because I don't like much of their music. I think that I was more attracted to them when I was younger because they had that outsider, taboo-ish quality. I remember in the 90's I told this black punk rock girl from Boston that I had a hhuuuugggeee crush on that I listened to Skrewdriver because I thought they were "funny" and I got my ass chewed out but good. She told me that in recent history (back then) in Boston that a large portion of the 'punk rock' kids started listening to Skrewdriver because it was "funny", like some kind of fad or something, and slowly but surely, some knucklehead used that as an in-road to convert a whole bunch of former non-racists into Hammerskins. So I guess it is a fine line, you gotta be careful with what you promote, what you support, and even the thoughts you let into your head.