Hey guys, I just wanted to suggest the Nuforce DAC-100 or the Nuforce HAP-100 as a good mid-price DAC/amp or amp that have good synergy with the HD800.
The HAP-100 is an amp only, with 4 RCA inputs and a variable output set of RCA. It has more voltage swing into low impedance phones than the DAC-100 but with high impedance HD800 the DAC-100 sounds very close - with 4 digital inputs instead of analog, and one variable output RCA. The HAP-100 sounds a lot like my $1200 maxed out (Vcaps & Blackgates) Woo WA-6 with the best tubes, but costs half as much with about twice the power!
The DAC-100 is not as good with low impedance phones as the HAP-100, and it has a higher noise floor with very sensitive low impedance phones and IEM. But for HD800 only it's better than my DACmini which can get a little fatiguing with HD800 over time. While DAC-100 is best with HD800, the DACmini is best with LCD-2, HE-500 and LA7000. The HAP-100 is like a combination of the best of the DAC-100 and DACmini.