Hey in case you haven't got anything yet, I'll throw in my few cents.
Mic wise, I would get a dedicated microphone. When buying a headset usually the money goes into the headphones and the mic is just an add-on. I have a mic that requires an actual audio interface to run but I'd get something like a blue yeti or a Audio Technica AT2020 (USB). If you want something clip on I'd look at the mod-mic, maybe a little pricey though.
Headphones wise, I can only really talk about what I use for gaming which is a pair of Beyerdynamic DT770s. They are closed back but are really nice all the same. A friend has a pair of DT990s which are open back so that may be more your thing.
Hope that helps.