Bass + Soundstage top priority around $150 = Beyerdynamic DT 990 Pro.
In my experience the Ultrasones are a bit lacking in the soundstage department.
Edit: I should clarify... My Ultrasone PRO 750s (new grey/black version with s-logic plus) are a bit lacking in soundstage IMO. Other models might do better, particularly the open back ones, and YMMV. That said, there are a whole lot of closed back headphones out there that have much narrower soundstages than the PRO 750. I agree that in that respect they're above average.
Edited by devhen - 1/23/13 at 4:01pm