I have an n800, a total bithead, and Grado SR225s. The DAC and amplification on the total bithead is phenomenal when listening from my PC. Headphone amps aren't about being loud, it's about correctly amplifying the waveform and not running out of energy when some bass note hits and uses up all the available power in the measely output stage of the amp.

If I can get the USB audio working on the n800 this will be awesome. Has anyone actually played FLAC back from the n800? It can be pretty CPU intensive to playback.