I have used various foam types, triple flanges, and custom silicone for my IEMs and I think those isolate better than any foams I've tried. But I have very narrow ear canals and have a difficult time getting the foam to stay small enough as I insert it. Plus, there's a huge cost difference. I'd concur with most of the others and go with the foam type if you can get them in place before they expand too much. Also, no need to be so snarky. People are just trying to help even if their post doesn't fit your exact parameters.
Edited by roadcykler - 9/1/13 at 4:15pm