I have done a lot of headphone research and some listening of late.
Its very hard to choose on paper these days other than style maybe. So many good ones and headphone preference is a very personal thing.
I really like the Klipsch phones I have heard, both in and on ear. Seem pretty flat top to bottom but with bass that sounds more right to my ears compared to many phones. I bought the in-ear buds and those are quite good for the money as buds go. The on ear models sounded similarly good when I heard them.
I am still a Stax fan also for the combo of sound and low fatigue and have a pair of older Stax electrets. These are hard to find in US these days it seems but I would go out of my way for Stax electrostat headphones still if I were in teh market for a new pair. Most Stax require higher voltage than most phones and run off speaker outputs via custom transformer though, not off line level as with most headphone amps.