I use the DT880's and K702's for acoustic-only music like jazz, classical and folk. I use the DT990's for any non-acoustic music. I use the 680i's for all portable use, without any amping.
Headphone Amp Inventory:
I don't even own a desk anymore, so I only look for equipment that: 1) sits unobtrusively next to me on the couch, and 2) doesn't require a wall power source. I've gotten rid of my old stuff and have pared things down to:
HifiMeDIY Sabre 24/96 USB DAC ==> JDSLabs C421 Amp
I own both the AD8620 (original w/silver plates) and the OPA2227 (newer w/black plates) versions of the C421, although I mostly use the OPA2227.
--MacBook Air w/Decibel for playback and XLD for conversion
--Nexus 4 Phone for most portable use
--Sansa Clip Zip for running
I have a mix of 24-bit FLAC, Redbook FLAC/ALAC, and MP3. I also use Spotify Premium a lot, which is actually decent quality at "-q9" Vorbis.
Indie rock, classic (acoustic) jazz, latin jazz, classical, and some techno. I grew-up in the 80's & early 90's indie scenes, playing guitar among other things. Nowadays, my musical sources tend to come from Bandcamp, Spotify, Pandora, and the "Watt from Pedro Show" podcast.