Grado SR-225 Headphones

I've had my pair for years. The bass is really great because they are an open design, and they never sound muffled as closed designs do. They portray the music perfectly IMHO, and can be driven hard and not distort. For me, the sound quality of these is a Reference which I compare amplifier-speaker sets to. The amp-spkr sets have always lost (but I stay under $3500 combined).

These sound great plugged into any normal headphone jack, but if you really want awesome sound from them, then buy or build a low output impedance headphone amplifier to drive them. They are about 32 ohms I think, so it's not as bad as a speaker at 4 or 8 ohms. I built and love the Class A headphone amp designed by Kevin Gilmore, see his site:
http://gilmore.chem.nwu.edu/head5.htm, but there are many commercial units too. I bought new foam ear pads at audioadvisor.com