Thanks in advance
Edit: I'm getting the schiit m&m stack. Headphone suggestions under 300 would be appreciated
Edited by Dgiant - 12/23/12 at 8:24pm
Equalize the headphones you currently have and spend 300 dollars on music. 
what's not-to-like about your D5000's? D:
Sennheiser HD598.
+1 if you can. Or get them used.

Sounds like the HE-400, but the budget is a problem. If you want to try something new, these would slot pretty nicely in between the Denons and the AKGs. The E7+E9 can easily drive the HiFiMANs. If you're really limited by the budget, best you upgrade the stack as you see fit, then upgrade cans later on.
Wouldn't that be a downgrade? Well, I guess if the 598's have strength where the D5000 don't. Don't know what weakness the D5000 may have. I'm even considering upgrading from the 598's to the D5000!

Not sure about the Hifiman metal or plastic. But the DT880 is balanced and the DT990 is bassy.