I have a number of headphones that I use for different purposes:
- The obligatory Sony MDR7506s: Love these, they're like the NS-10Ms of headphones. I use them for as much as possible when external SPL allows. I use them for any critical listening I might have to do.
- Sennheiser HD280s: I have 4 or 5 of these. I use them when the external SPL is too loud for my 7506s (because they isolate so well). I also use them in the vocal booth because they limit bleed so much. I try not to use them if I can help it, since I think they sound fairly "muffled"
- When listening to classical music or the such, I love my Grado SR80i headphones, but they get uncomfortable after a while. Great natural sound though.
- For in-ears, I have a pair of M-Audio IE-40s (made my Ultimate Ears, distributed by M-Audio). They don't have traditional drivers - they use a triple armature driver system, and have an amazing bass response, and incredible isolation. I can be listening to my iPod at half volume and a subway will go by, I won't even hear the subway in New York City (NYC). I use these for listening only while biking, walking, all the time in NYC, etc...
- I've saved my favorites for last. My Beyerdynamic DT880 PRO cans. Pure bliss. Amazing. Slightly hyped, but amazing low end response, super smooth high end, and AMAZING localization. Almost sounds like you're listening to speakers. I like using these for listening to a final product. Its my equivalent of pumping the mains for a client versus critical mixing on the near fields. Also one of the most comfortable pairs of headphones I've ever worn. 6, 7+ hours no problem. They're semi-open back, so they have nice ventilation, and of course they have the famous velour ear pads. Fuzzy! Gotta love these guys :-)
What's your headphone collection like?