Use high quality tips like the UE silicons and stuff some foamies underneath. That way I get decent isolation. The 3580's sound quality is worth the effort.
Neither are the SHE3580 bass monsters if you drive them from a flat source, they have good balance with only slighty enhanced bass. But they do scale nicely with EQing if you're a basshead.
I agree, thanks to you both for the great find.
Now for something completely different... (opens Isurus package)