I apologise for the late response,the hfi 580 would work and has more bass than the others I recommended. They are IMO a bit lower in overall SQ and not as good for rock but better for dubstep. If you end up liking the sound then you can later save up for the pro 900(the best headphone for electronic music IMO) which sounds similar just substantially better SQ. So either would work for your wants and opens up a nixe upgrade path.
Ultrasones (hfi 780 or pro 750) would probably be what ylu want unless you can't deal with brightness or the long burn in. Another option would be the dt770 though they depend on what your running these with.
Edit-Also AKG k550 and Philip L1 can be found around $250,both I recommend over those
I previously mentioned but aren't as good for dubstep IMO as the Ultrasones.
Well the pro 900 tends to suffer with classical and is ok with rock, but its amazing with electronic music.The akg k550 is more an all rounder and does really well classical but dosn't suffer really in any area.I havn't heard the T7 so I can't comment on that.If its worth anything I love my k550 alot more than my pro 900 and unless Im going to listen to alot of electronic music I use it.
Since you want a more nuetral sound with a little bit of bass, the m50 and the dennon 2k(basshead amount) arn't the best choice,seeing how bass happy they are.I feel somthing along the lines fischer fa 003(clones) or akg k550, would be to your liking since there nuetral with a nice amount of bass.