James, I currently own the AH-D1100 and a coworker of mine just purchased the M50s. I can tell you from my experience the D1100 are great headphones for certain genres. In terms of rock and instrumentals, I would suggest the M50. When I first received my Denons, I was thoroughly convinced something was wrong with my ears. It took me a good two weeks of listening to music every day to get over the initial fatigue of pronounced lows and recessed mids (really recessed). I had to do a lot of EQ work to bring the mids and treble out. Someone on here had a good EQ setting that I used, and it worked well. That being said, I've owned them for about 7 months now, and I don't need to EQ them anymore. My ears have gotten used to them, and I love the things. After listening to my coworkers un-EQ'd M50s, I can say for sure they would be better suited for your musical tastes. On top of that, I have treated my D1100s meticulously since I got them, and they've developed several cracks around the plastic arms / fixtures. This is a common problem, as they're not built very well. My personal suggestion would be... only go with the D1100s if you're a basshead, and don't mind equalizing and poor build quality.