Try the SoundMagic E30's - amazing sound , really light and stay in a treat even on long runs - even better when the eartips are replaced with the Comply ones. I moved from Sennheisers a couple of years ago now and would never ever go back now...
Another recommendation for Soundmagic - here is my brief review from Amazon
This review is from: SoundMagic PL30 In - Ear Sound Isolating Earphones (Electronics)
I bought these specifically for use when running and really wasn't sure how the design would work with both running and the fact I wear glasses - couldn't be happier.They are very comfortable, light, beautifully made, the earphones never fall out ( and I tend to be out running for at least an hour ) they also sound amazing. Took some time to get the right size foam tip and its important to use the cable "toggle" so that there is good cable tension by the back of the neck once the earphones are on. One of the best purchases I have made for ages and would urge anyone who weares glasses and wants great quality "sport" earphones to give these a try - highly recommended! PS. All the hype about Comply Foam Tips is true - treat yourself and buy some, it really does add that extra bite to the soundstage.