Hey! That Yamaha receiver is plenty amp, AND it has it's own headphone surround processor. If you look in the manual, it's called Silent Cinema. You just have to enable one of the sound DSPs, I liked "action movie" best, YMMV, but it'll at least give you an idea about what virtual surround is like. Play around with the different DSPs to see which you like best. You can also boost/reduce treble and bass on the receiver
You might end up preferring a different surround processor, but Silent Cinema is definitely worth checking out and will get you most of the way there... and you already own it! That's a pretty nice receiver, IIRC.
Cheap headphone for all purposes & portability = Koss KSC75. I believe I already recommended it. It's not the most exotic looking or boutique, BUT it delivers where it counts. BY FAR better than any earbuds, even Yuin, and holds up against $60-$70 headphones. Just try that first, and if you like gaming/music with headphones, get a "reference" headphone to use at home with a good return policy, in case you don't love it. That's how Mad got started, and I could've saved money if I had done that.
Next steps, consider JVC HA-RX900 with Dynamat added inside the earcups to tighten up bass, Creative Aurvana Live!, Grado/Alessandro headphones (grados are great rock cans, Alessandro's are more balanced & respond well to MS1000 mod), Takstar, DT770, DT990/Q701 (equally good but different signature emphasis, different things to love), and up up and away!