I've really enjoyed the TH-900 with Supercell, Kana Nishino, Bump of Chicken, and many anime/game OSTs. I think one of the strengths of the TH-900 is that it does well with every genre. There hasn't been a standout genre where I thought "This is exactly what the TH-900 was made for", but it does no wrongs.
Heard a couple pairings so far, my personal preference stays with the Fostex HP-A8C. I'm sure others have heard more than I have and will be able to give you their thoughts.
Nice, so it is an all-rounder headphone. Seems a few reviews have bias about the Fostex TH900, especially when paired with specific amps and DACs. I'm still looking around for an amp, DAC, or combo unit to pair with the TH900.