Since you mentioned not liking how closed the Beats are what about the Denon AH-D2000? They are still listed as closed phones but in actuality they are somewhere in between so fairly easy to hear either way but not as bad as open phones (like Grado). I just tried these out in an HMV next to the beats and they sound quite a lot nicer IMO. The bass goes up and up through the range (5000 / 7000) but so does the price.
I just bought the Denon AH-D7000's and the bass for dubstep is just magical! The D2000's are cut from the same cloth / similar audio characteristics. They are big-ish but not heavy like the metal Beats. I agree with SkinnyPuppy's recommendation for nice quality with decent-ish bass (also they're all smaller). I own the Sennheisers and truely love them but they are closed with good isolation like the Beats, as are the other two I think and it sounds like you are looking for something a bit more open.