Depending on the quality of your itunes really good headphones may actually be a bad thing. Sometimes a loss of clarity nicely hides compression artifacts and losses in the source material. That being said, I like my relatively cheap Sennheiser over the ear closed back set, they were under $30 from Amazon a year or so ago. I've never experienced Grados though, and everything I've ever read says they're hands down the best.
For a boom mic headphone, I use a similar Plantronics to the one noted above at work, clear conversations over 100' from my office (but strange looks from my coworkers). 2 years of use and it's holding up fine. A handset lifter is a great addition to one of these; when we recently changed phones in the office I couldn't use mine anymore. Having to push the phone button to answer vs just the button on the side of the headset sucks now.
