If you’re thinking about headphones to wear for hours, I find the circumaural (cushion goes around your ear) ones are much more comfortable.

If you’re in a shared space, a closed back set will insulate you from room sounds — and the room from your music. The open ones give a more ‘airy’ sound and IMO a better ‘soundstage’.

If you’re trying to decide between models, check out head-fi.