So, let me get this straight:
-$70 or less
-Good bass response
-Isolating
-Nice aesthetics
I think you might like the Philips CitiScape Uptown. It isolates (well enough with music playing that you probably won't notice most outside sounds, and doesn't leak sound), the bass is pretty good, and it does look quite classy.
Most pairs are over the $70 mark now that the sales are over, though...but I can help you with that.