Sennheiser HD25 since a week or so. Before that, I was using a pair of px200 (the same pair for almost 10years). My commute profile is 15min of walk and 30min of subway (each way). Quite a lot of subway on top of that. I can't stand intra so no IEM considered...
- sound: they sound quite good :-)
- strong noise isolation: it's a big plus to be able to hear the music properly without raising the volume up and up.
- frequency response: a slightly boosted bass range compensate the isolation being less effective at LF.
- robust construction: I'm not affraid of tossing them in a backpack nor too scared of the rain.
- high sensitivity: no real need for an amp in a portable situation, any half decent phone will power them directly (even the 600R version I have). I don't want the bother of carrying an amp.
- long term reliability: all parts can be changed and they have a 25years track record for reliability.
- size : they are quite small but don't fold in any meaningful way so they take more space in a bag.
- cable: for some weird reason, it's entering on the right cup which isn't very practical.
- price: I found mine used at half the street price for a new pair. But they're not cheap new.
The px200 had some advantages, mostly in folding very neatly. I could carry them in a coat's pocket which is why I kept them for so long. But the isolation was poor... after a week with the HD25, I don't see myself going back.
I considered quite a few other cans over the years and especially in the last months. Going back to the mdr-7506 was a possibility but isolation isn't that great and they sound too agressive to me. The focal spirit one is rather nice sounding but I was worried about durability and solidity. The Beyer dt250 is big and has an unwieldy cable entry plug. A sennheiser momentum on ear was the strongest competitor but the relaxed sound wasn't to my taste. That and I prefer the kind of industrial look of the hd25.