I was always a hi end home audio guy. I sort of fell into the IEM addiction on accident. I had Bose noise canceling headphones for years for long international flights I tend to take often. They worked wonders for fatigue. It may be just be, but when I landed I would be exhausted without them even if I slept.
I forgot them on a trip once and ended up buying Shure 310's. Oddly enough, while less sound made it to my eardrum, I don't feel as though they were as good an option as the Bose for fatigue, but still totally acceptable. I'm sure a lot of this is just my brain playing games with me, but just my opinion. However, they are still totally acceptable from a fatigue perspective. I've gone so far as to use both at the same time.
In any event, for noise isolation and extended use, I prefer foam tips. Id suggest either the Shure Olives, or the Monster SuperTips. I've tried everything and I'm a huge fan of the Monster Supertips now. Don't waste your time on the Comply Tips, they destroyed the sound quality for me, at least on my Sennheiser IE8s.
One other thing to consider is the size of your ear canal. I'm blessed, I have pretty large canals and can fit a small child in them. But, my girlfriend has tiny canals and I bought her a pair of monster coppers that didn't fit at all. Shure's have tiny tips and can fit in her ear just fine.
