Guess I'll start off with a little background here. I made my first foray into "higher end" headphones around a decade ago with a set of Sennheiser HD-280 Pros, which served me well for around 5 years until they literally started to fall apart (plastic headband cracked, and is held together with electrical tape). I mainly drove them off an older AV rig with an SB Audigy Platinum.
After wearing the HD280s out, I demoted them to backup only duty and picked up a pair of ATH-M50S cans along with a Samson S-Monitor amp, which have been serving me well for ~4 years now and have proven much more durable than the Senns ever were and are a huge upgrade in sound quality as well.
The time has again come for me to pick up another set of cans, as I'm looking for something to use at work (M50s will stay at home). I was originally planning to just pick up an identical setup to my current gear, but discovered the S-Monitor is no longer available, and after a bit of reading found that the price of the M50s have gone up and the cans have been redesigned.
Given that I listen to a wide spectrum of music from R&B/Hip-Hop, Rock, Electronic, and Jazz, I want a setup that will be well suited to a variety of content, will be comfortable for long periods of time, and I'm hoping to stay in the $100-150 price range for cans and $50-100 for an amp. Primary sources at work will be either my iPhone5 or Macbook Pro Retina.
Anyone have any suggestions or advice as far as what to look for?