Will this be for gaming? Do you want open back or closed back? Will these be used a lot in a quiet setting? How big is comfort to you? What kind of music do you listen to? Will these also be used as portable headphones, if so, with what? An Ipod? Zune? How about the looks of a headphones? If an amp is suggested, do you want it to be ultra portable or just regular?
Any cans over 150$ will more then likely need an amp, so
. And then there is the issue of the interconnect... haha.
Some off the top of my head - DT770 Pro80's (180$ish), ATH-A700's(130ish), AKG- K81 Dj,Sennheiser HD-580 with 650 cable (220ish + cable, but you can find em as low as 160$).