I've tried pretty much every commonly available studio-grade headphones you can think of up to $200; of all these, the ATH-M50s are the only ones that give a nearly accurate representation of what you're monitoring. The others I auditioned were too colored (Sennheiser), offered poor bass response (AKG) or simply didn't provide enough detail (Beyerdynamic) to be used for actual studio purposes.
With that in mind, I'd blame your source material and/or other hardware for that before I would the headphones. Then again, I suppose it's moot if you're only using these for listening and not actual music making (and yes, I actually use these on studio gear for my own amateur musings).
Like I said, they're not perfect, but at this price point? You'd be hard pressed to find anything that outdoes them in their respective category.