I've tried both the 7506 and the V6 (which are the same thing) and I can recomend them too. They are fairly dynamic, though they didn't seem as flat to me as some people say, not that's a bad thing for dance music though. The bass is good, the detail is there, and the "shrill" highs some people claim to experience with them didn't bother me at all. I supose the test for me would be to listen to the beginning of "I Can't Wait" by Mirwais.. But I haven't done that. For a $100 budget I can't think of a better phone for you, but I haven't heard many of the other sub $100 favorites, so that in and of itself, doesn't mean much. However, for use with dance music and no amp I don't think it will be easy for you to go wrong with these. If your budget were higher, I'm sure most everyone would be saying to get a cheap DIY amp and Beyer DT770s... But that's way out of $100, so the V6 is a good choice. They don't really need an amp either, which is good for portable use. As for isolation, they do isolate sound, but not an awful lot. It's enough that you can't hear much around you when music is playing, though I find that I can't talk to people with music going even in open phones.. I'm not sure how much ambient noise, such as from a car, there would have to be before you could hear it, but certanly they block some. They also fold up and people say they are quite sturdy. From the build quality, I immagine they're right. Have fun.
