I just got a pair of Shure E2C's. I read as much I could find here on head-fi and found other reviews on the web.
I find that these in ear phones are really well made. I plan to carry them around with me and use them while I am exercising. Thus, build quality was a very important consideration. I also considered the er6i's from Etynomic Research but the cable looked too flimsy for my purpose. They also cost a bit more than I really wanted to spend.
Unlike many, I have found it really easy to insert these and get a good seal. They are comfortable in my large ears.
These are used plugged directly into my ipod shuffle. As for the sound I do find that the highs do seem somewhat muted and the bass is a bit bloated. They are way ahead of the stock ipod ear buds, however. They do lack the tightness and balance of my home phones, a pair of HD 580's.
I bought these for $66 with shipping and I've got to say that I feel I got my money's worth. I wanted a pair of phones that would have decent sound, excellent isolation and sturdiness. I think I got all of these for a fair price. I don't think, however, that I would be willing to pay $100 for these phones.