I wound up ordering a pair of Beyerdynamic DT-880s despite the mixed reviews they've received. Amazon.com's $169 price was just too good to pass up. If I hate them, I can always return them.
Now about an amp.
I've got two amps here at home: a HeadRoom Total Airhead and the Citypulse 7.2 DAC with a built-in headphone amp. I've been researching standalone headphone amps and would be interested in opinions.
* I understand tubes probably complement the DT-880s better than a solid state amp, but I prefer the convenience and cooler operating temperatures solid states offer.
* Amp has got to have a loop or preout since I intend to put it in between a DAC and a stereo amp.
* I'd prefer to buy from a U.S. dealer.
* I'm willing to spend up to $900 but would prefer to stay in the $300 t0 $500 range.
Among the amps I'm considering:
*Gilmore Lite ($399) and GS-1 amp/preamp ($899)
*Headroom Desktop Amp ($699) or Millet Hybrid ($599)
* Little Dot MK III, IV, V ($159 to $399)
* Shanling PH100 ($400) -- Russian tubes, though. How easy will those be to find?

* Firestone Little Country III ($500)
* Stello HP 100 ($595 + $85 shipping)
* CIAudio VHP-2 ($399)
* Musical Fidelity X-CANv8 ($549)
* Pro-Ject Head Box SE ($199) -- two headphone jacks, three sets of RCA inputs, and RCA output.
Anybody heard these? Heard them with the DT-880s?