for $100 go with the Shure SRH440, Philips Cityscape Downtown or Sennheiser 428.
Amazon.com: Shure SRH440 Professional Studio Headphones (Black): Musical Instruments Amazon.com: Philips Accessories SHL5605BK/28 CitiScape Downtown Headphones (Brown): Electronics Sennheiser HD428 Closed Circumaural Hi-Fi Headphone (Black): Amazon.ca: Electronics
The Philips are a bit warmer and more enjoyable for music. I use them for everyday music listening. The Shure are more nuetral and a bit harder to drive. I love using these for movies and games. Definitely benefits from a PMP with an amp or an external one. They're a bit heavy and can use some extra headband padding. The senns are completely nuetral, easy to drive and a joy to listen to. The really long cable drives me crazy though. I use these to listen to music and fall asleep with.
I have all three and love them all. Each has different purposes and strengths though.