Well, my in-laws puppy got ahold of my iBeats for my Rezound, so after trying 3 different IEMs at Best Buy I got a full refund and said screw it, went online and did some hardcore research. Here's what I found...
A lot of people recommend the Klipsch S4s. Don't get them. They're overrated. I went through a bunch of researching and in the end I found so many people who bought them and were utterly disappointed with them. Instead I found this no named company called Nu Force...
Nu Force NE-700X
I love these. They were $52 refurbished and they sound better than my $100 iBeats. I've never listened to the Monster Turbines (which are $200 earbuds), but many people say these are the best IEMs under $100 and that they're just a notch below competeing with the Monster Turbines in terms of overall sound. Best bang for your buck in other words.
Some nice things about them? The silver parts are all made from aluminum and they have titanium coated drivers, they feel pretty light compared to the Rezound iBeats I had, but at the same time they don't feel cheap. They make just as good of a seal and isolate sound decently well. YOu could probably do even better if you bought the supertips for the buds. The cord is prone to tangle like a regular cord, but you can also use your clip on the cord as a doubled guide to help keep the cords apart as well.
Overall the sound in these are great. They give very decent bass and good soundstage presence.
They also made the exact same version, but it comes with a pause/play button and has a mic. Although some people say when it's plugged into your phone you can hear the background noise on the mic while you're playing music. not sure if I'd want that.
Nu Force NE-700M
In the end, if you're in the market for some earbuds that have good sound $100, I recommend these There's only a few others that compete with them in this price range and those are actually more towards the $100 range while these are $50 to $65.
The only thing I wish they had were more colors. You either stuck with silver or brown.
Here is a very good in-depth review of the NE-700X on head-fi.org...