how to know which headset is better?

I need a headphone(on the ear) under 2k...and also is there a headphone which have surround sound and what will be its price...microphone is optional...
and
i dont understand the things that are written on it like impedance,senstivity,etc...(i am completely new in audio) so plz can anyone give a little overview on hardware of a headphone....like if something is more then it is better..something like it....