Taking price into account above all else, these are the best headphones I have ever owned.  Obviously my HD650s and DT880s sound better, but they also cost 15-25x as much. I've probably put ~150 hours on them. I did do the kramer mod (involves drilling a few holes in the driver cover to allow more sound through) but they sound great even without the mod. I also bought a Parts-Express headphone from Amazon, took the garbage drivers off them and snapped the Koss drivers on. I find them much more comfortable this way. As a plus you can bend the headband...

I'm just gonna start off by saying I love this headphone. It has dominated my head time since I got it. My HD650 gets no love anymore. They are just incredible. They're easily worth $400 in my opinion.   My first serious headphone buy (HD280 5 years ago not included), I got the 250ohm version and used it with an E17 for a month; I ended up returning them to Amazon due to getting the HD600 and HE-400, both of which I ended up selling and returning as well. I couldn't justify 2 pairs, let alone 3. I got the HD650 and it changed everything. I ended up...