Sony's MDR7506 is, or at least used to be a few years ago, the reliable radio workhorse. When you spend all day with your headphones, especially in the field, super expensive cans most people like for music are a liability. I love the 7506s: flat, cheap, and comfortable all day. <$100. NOT the consumer version (-V6 or something). Real, purebred, MDR7506. NegativeK is right, too; the $100 AKG range is also popular in working radio, as well as some Sennheiser HD280s.
On the production side of things where quality super matters, you'll see the more expensive headphones for sure. But every single person in the last newsroom I saw rocked the 7506, and though I've moved on to more expensive headphones for programming and my music collection, I still miss my 7506s on occasion.