I was looking at the Beyerdynamic DT 990 Pro, but I was wondering whats better for $275 or less. I prefer over the ear to on the ear. Closed back or open back. Doesn't matter there. Also a largeish soundstage is nice.
I can't think of anything right off, but you may want to check out the new VModa M100 which is due out shortly. If it retains the M80's best qualities and since it's larger and around ear (I believe), it could be a real winner.
Edit: I did find the Philips L1, for $299 which is close to your price limit(?), and it's the best sound I've heard in this price range. So that might be the best bet.