I'm somewhat surprised that nobody has really mentioned the issue of jitter. Reading the data without errors is not the problem (in a PC), but the data stream going out is still controlled by the internal clock (on the sound card), which the clock in the DAC syncs up with. Here's an excerpt from a review of the Lynx 2 audio card:
"Some time ago it was assumed that high-quality sound could not be obtained at all on a computer system because of magnetic pickups from a video card and a processor into the sound card's circuit of the printed-circuit board, terrible power supply from a pulse power supply unit, jitter in converters, inadmissible usage of transfer electrolytic capacitors, low-quality connectors, cheap components of the analog section. " [http://www.digit-life.com/articles2/lynxtwo/index.html]
The best approach seems to be to have the master clock in the DAC circuitry and have it control the transport's sending clock, or have them be one and the same. The latter may be done in integrated CDPs, the former can be found in products from Wadia and dCS as well as high-end audio cards (Lynx L22, LynxTWO, Emu1280M).
Like many of you I'm in the process of capturing all my CDs (to ALAC - Apple lossless), but I'm not sure a $100 or even $200 sound card will do high quality headphones or speakers justice.
BTW, some of you were looking at controlling the music remotely, and the touchpad option is certainly a good one. Something else to consider (especially if you aren't overly concerned with jitter coming off a hard drive based source) is the Sonos music system. I own several of their zone players and controllers, and it's great for listening over my built-in speakers. It's biggest plus is ease of use (very reliable, intuitive, and a killer interface especially with the little wireless remote). The built-in DAC is ok but not the greatest, but they are coming out with a zone player with digital out, which would let you use an external DAC and amp (not sure about jitter though). Highly recommended!
Frank