[RedLeader]

I enjoyed the 75s, unless it was windy. It was more of a problem while biking, but it still holds true while running. I could actually hear the diaphragm crinkling in the wind. Needless to say I now use EP630 when I'm biking as they don't isolate much yet aren't bothered by wind.

 

[tohni]

Bit late, but anyway, here's my two cents: the KSC-75s are WAAAAY to warm for me while running.
I'd go for cheap IEMs. They won't fall out and you don't have to fear having them destroyed by sweat.

 

[FooTemps]

I've found that most headphones are good for running as long as they're lightweight. Buds, small band supra headphones, and clips all are non-intrusive enough to go running with.

I've used various senn buds, ibuds, ksc-75, ksc-55, px-100, and more for running and I say they all work out fairly well. Some forms are better depending on your head size though.