Basically it's good for all genres (or just the ones you listen to) But It's not the best out there for particular genres.
Senn 558's nail it pretty well in my mind, but upgrading soon.
I think it's time to look into the new breed of headphones.
I'm gonna go with the Focal spirit and NAD.
The HD600/HD650 had it's fair run, their weaknesses are well known. I think it is time for both of them to step down and make room for the new generation of headphones...they can all go down to 20hz flat with very low distortion everywhere.
* might throw in the Alpha dogs as well...pending measurements to show up at inner fidelity.