rvpiano,
I've been a headphone believer for decades; currently, I splurged on a set of the HiFiMan HE1000 (an insane $3,000!). But the Sennheiser line is outstanding for the money, if you can use an open-back design. The HiFiMan is so open, by the way, that one can listen to it without too much loss from several feet away.
FWIW, I'm also a believer in the HeadRoom headphone amp with its crossfeed processing circuit. The circuit's effect is very subtle; the only dramatic way to confirm it's doing anything is to unplug one of the channel leads while listening. With ordinary amplification (or the processing circuit switched off), the result is like having one's head split in two, or going suddenly deaf in one ear. In other words, not at all like disconnecting one speaker of a stereo pair. But with the processing circuit in, the effect is startlingly like losing one of a stereo pair of speakers. You still have a 3-D sense of space, even though all the music seems to be located at the still-active earcup.
Of course, no one listens to music like that. So what is the real world effect of the circuit? Well, less headphone fatigue, for one thing. And the music really does seem to be coming from in front, rather than being piped directly into your brain.
There are several versions of this device, and used ones are available from time to time on eBay for $200 or so, depending on the model. They're all very well made.
Incidentally, the mind behind HeadRoom is Tyll Hertsens, an interesting person in his own right.