HD580 is a bargain for its sound quality and its $125 price. This used by be Sennheiser's top of the line dynamic headphone before they tweaked it (mainly different grille) and introduced it as the HD600. Now the HD650 is the top of the line but many people prefer the HD600 still. However, note that these are pretty inefficient phones with high impedance, so some people say it won't sound as good without a headphone amp (out of an iPod)
I don't think many people think too highly of the Bose Triports or the Sony V900 (the V6 is still the gold standard among Sony phones).
Grado is another brand to consider. I personally think their quality control is pitiful (they look like they were assembled by high school students, poor quality molding, big gobs of glue, uneven paint on lettering etc), and they sound too bright.