My HD497s are open...and I like them that way. I do sometimes need to hear what's going on...as I live alone in my apartment...but that also means, other than the fridge, there is little noise. My PC is pretty darn quiet.
I currently own the HD-497s...I like them...they are amazingly comfortable...I just want the next step...also something with one cable (on one side).
I know the HD 600s and HD 650s are loved here. I am also strongly considering the HS 595s.
I notice you have the UM2s...
UM2 = ??? in terms of full-sized cans?
Hooked up to a computer / SB X-Fi.
I listed to a lot of female vocal trance.
But also game, listen to soundtracks, rock from time to time, etc.
Edit: They should be supremely comfortable...like I don't know they're even on my head. And I am woeful of overly bright highs causing fatigue.