Best sounding headphones you have owned?

Anything from JM Audio Design - John Massaria is nothing short of a headphone savant.  

I was a soldier all my life & now retired so I've never had deep pockets for audio gear & being a firm believer in trickle down tech I have always looked to the manufacture's for the best value in their product lines.After extensive demos of the TOTL from Audeze,HiFiMan,Focal,Sennheiser,Grado & AKG I discovered I like the HiFiMan house sound,settling on the Sundara for exotic driver tech & the absolutely amazing iBasso SR-1 limited editions(500 pair)for dynamics...
 Where the Sundara is virtually dead neutral & fast as lightning,the iBasso is relaxed,lush,dripping with harmonic richness & tonal color that is not unlike the finest 300B amplifiers...

@freediver Sounds like you found a great match, and I’m obviously with you on the Hifiman sound.  Congrats and enjoy!  Oh yeah, and most importantly, thank you so much for your service!!!

Audeze LCD-4 are my best, but the Sony MDR-Z1R are a very close second for a lot less money.

State of the art sound for a relatively low cost is one of my headphone systems:

• RAAL CA-1a (like regular headphones, unlike the RAAL SR1a) ($2000 naked version)
• RAAL TL-1a speaker adapter box ($800)
• Schtt Mjolnir preamp ($1100)
• Schitt Aegir amp ($800)
• Benchmark DAC3B ($1700) (dual duty with my 2-channel)

This above setup is so good that I threw out all the shipping boxes. I live close by to RAAL and Schitt if service is needed. I cannot easily sell this gear now. I also use the more expensive RAAL SR1a phones with the above setup.