I'm on my third set of these:
Sennheiser CX 300 headphones (black) Headphone reviews - CNET Reviews
I just wear them out, get them hung on stuff etc. If you're the type who likes in-ear earbuds, try it. The sound is incredible, and the price is super.
I've tried lots of headphones under $100 - LOTS. And I keep coming back to these.