There are quite a few here who use headphones professionally. I'm not a pro, but am a big fan of pro headphones.
One model you'll find all over is the Sony MDR-V6. They're used for a lot of recording, at radio stations, everywhere. Sony has a full pro line of headphones. I like the MDR-7509HD and usually use them when I travel.
At the high end, the AKG K-1000, Grado HP-1000 and Stax 4070 are pro headphones.
Beyerdynamic makes several pro models, too, like the DT150 and my favorite, the DT48.
AKG and Sennheiser make a few as well, but I'm not familiar with them outside of the K-1000 and the widely used HD-600.