My headphones & IEMs say that I'm a very choosy person, and am always striving for the best possible sound. Therefore I don't collect hundreds of pieces of gear for that sake alone, I only keep a revolving set of several items which best reproduce the music I love listening to. It's always an upgrade path for me I suppose.
My current favorites are:
FitEar To Go! 334, Vsonic GR07, and for full-size Fostex T50RP RP2 modded.