I'm kind of an expert in headphones, and maybe I can point you in the right direction.
Although it sounds good with some types of music, I'd stay away from the MDR-V7000DJ. It's best for a heavily colored rendering of louder music, but it's a sledgehammer of a phone. For half the price, you can get the the acclaimed Sony MDR-V6 (V6 for short), which has a very flattering sound with all types of music.
But for the same price, you might invest in a set of Grado SR-60s -- said to be the best phones available under $100. You can get a discount here:
http://www.toddthevinyljunkie.com/products/product.php?id=129.
With the money you save, you can get a headphone amp. (The term "headphone amp" is somewhat of a misnomer; actually, it's an amp that helps purify the sound of CD players, iPods, etc.)
Sennheiser and Beyer are also fine names, but sound varies. My Beyer DT-880s, just purchased and broken in, are absolute knockouts.
PM me if you have additional questions.
:headphone