Just my 2 cents...
I never liked the sound quality of the noise canceling headphones... used them for years as a pilot for communicaton and they were great, but they make music sound tinny, at least to me.

I really prefer the Shure noise blocking are amazing. I'm constantly hearing new things in songs.

However, I have taken them to the gym and the one word to discribe it is: gross. I sweat a lot and it runs into your ears and they get all wet and make this sucking or sloshing sound... I got a cheap-o pair of sony over ear earphone for running and the gym...I can hear outside noise and it doesnt feel disgusting.