I would also consider IEMs. Commuting with headphones is troublesome to say the least. Not to mention when you're not using them, they needed to be stored somewhere. Open headphones do leak a fair bit, but not as much as some people think that they do. At medium volumes in a vibrating bus, there is not that much leakage. I've used the Q701 once on a bus, just to test, and I didn't hear my music when I took them off.
If you consider IEMs, I would also recommend Etymotic. I don't own a pair, but very much so want a pair. Their higher end offerings sound great (so do their lower end), and hvae a claimed 85% accuracy. So they're pretty much an all rounder if you're looking for one.
The isolation is as good as they say it is, pretty much amazing blocking off almost all external noise. But that can be dangerous while walking/ crossing roads.