I started with a pair of ATH-AD700's about three years ago, added a FiiO E7 last year, and then grabbed a pair of AHD2000's in June. Now I'm looking to invest a bit more money into this.
My computer is my source. Output options are USB, coax, or optical from my onboard sound. Depending on when I ripped/purchased my music, it varies between FLAC, 320 kbps, and 192 kbps. I'll be working on replacing all the music I still listen to with FLAC over the next few months. I primarily (by a large margin) listen to folk and indie rock, with an occasional mix of just about everything else depending on my mood.
My hope is to purchase the headphones and dac/amp within a few months of each other, though I could manage to get them at the same time. I intend to spend ~$2500, but that is somewhat flexible if it seems justified.
My current research is leading me towards HD800's, Schiit Bifrost, and either Lyr or Valhalla. I am open to any and all suggestions.
I tend to wear my headphones for long periods of time, but I usually don't keep the volume terribly high. I would prefer to purchase the headphones first, but could go the dac and amp route first if the headphones I ultimately decide on need more power than my E7 can deliver.