I was very happy with Shure for quite a long time, occasionally jumping over to Etymotic. But the last time I lost mine, I did rather extensive research and ended up very happy with the VSonic GR07 - they're more, but not crazy more ($160 at Amazon).
Here's a thread with reviews/comments -
Vsonic GR07: Perfection
head-fi is a good place to research - it's been 3 years since I bought them so there may be new stuff out there. I'm sure there's a recent "what should I buy for $100" in the forums somewhere.