I've been using closed/sealed headphones of various sorts pretty much exclusively for the past 20-odd years. I've run, well, not nearly the gamut (go look for ijokerl's comprehensive shootouts for that) but enough from relatively inexpensive but still good at around $50 to relatively expensive at $300. Swapped pads, modified pads, taped bass ports, and performed pretty much every easily reversible modification that I could find but never got anything better than good enough and more often not even that.

I recently got fed up with my latest try (SRH1540 pads on ATH-M50 headphones) and for the hell of it dug out my Koss KSC75 clips. I was amazed. I'd forgotten just how good open headphones can sound. That's from a $20 clip-on headphone. So, I spent an hour or so auditioning Grado headphones over at Q Audio. Yep. I walked out with a SR80e. And I remembered a video that I saw last month:

https://www.youtube.com/watch?v=3fD-M1F6L4g
It's titled "Gaming Headsets Suck - Make Your Own For $50 or Less"

While the video is focused on gaming the information is good for headphones in general.