I'm with xyclear. I have both a set of PC 350 and PXC 350 (noise cancelling) and I must say, I love them both to death.
The PC 350 set is really great for gaming, and the mic sounds good to others, though I find it is highly directional, so it has to be in the right spot for them to hear me. It doesn't pick up any background noise, though.
The PXC 350 set is noise cancelling, which I use for work and travel. All 350 series have a very high impedance, which means normal sound cards can't quite produce the sound quality they were built for, but the PXC 350's noise cancelling unit (built right into the cups) also acts as a very decent amplifier. So, whenever I want to hear something in very high fidelity, I turn on noise cancelling, even if I don't care about ambient noise.
For true quality listening at a fairly reasonable price, I'd say go with the PXC 350, as it can be had for around $250. Best money I've ever spent, I think. Also, interchangeable and replaceable parts ftw.
The very best sounding headphones I've heard, though, were Sennheiser HD 650s, I think. A friend had them hooked up to a really expensive amp. It actually might have sounded better than real life. They cost him over $600 just for the headphones, though.