I'm a longtime Head-fi member, first set of workplace cans were HD-280s about 10 years ago. This article is a decent start, but there are many better options in these respective price ranges. Head-fi is there to help - http://www.head-fi.org/ I've moved considerably upmarket over the years and won't talk about the rest of my setup, but my main cans now are Ultrasone Editions 8s. They're very pricey (retail $1500 for…
They're closed, but not super-isolating, a good tradeoff between not leaking sound, and being able to hear my phone ring.
They're very comfortable, more so than other phones I own (At home I have a couple different pairs of Grados, Beyers, and AKG 301s).
They also drive well of a standard headphone output, when many audiophile grade phones (the AKGs and most higher-end Sennheisers, for intance), don't.