Darkjedi... keeping things purely digital in a PC is not as easy as it sounds! That Oxygen chip certainly looks impressive, but so far CMedia has not enabled ASIO functionality in their latest series of chips, so sounds will always be "adjusted" in the windows mixer (or whatever OS you might be using that CMedia supports).
Let me give you a good example how the analog outputs of these cards might in fact be better than staying with a pure digital signal...
A person is using a high quality music or lossless format and plays it on their system. Let's say that it is a 24 bit/96kHz sample. The X-Plosion handles this in one of four ways.
The first is to send that information through its onboard DAC as a 24/96 signal, out through the OPAMPS, and then to the speakers/amplifier. If the user is taking this music and converting it to a 5.1 signal (up Matrix) and out through the 5.1 analog ports. Staying with the analog outputs keeps things fairly clean, especially if the OPAMPS are upgraded on the card and you have good speakers.
The rest of the three ways to do this rely on the quality of the DAC's on the receiver you are sending the digital signal to (PCM, DD 5.1, and DTS). Most PC enthusiasts are using the Logitech Z series of speakers which have the decoder onboard. Unfortunately, this decoder is not of great quality, nor are the DACs all that great (Logi allocated the majority of quality components into the sub, speakers, and the amp... the decoder is actually fairly crappy). So, instead of relying on the pretty good DAC on the X-Plosion, the Logitech receiver takes the digital signal from the card and uses its own decoder (again, a poor chip) and its not-so-hot DACs. So, in this case, even when using just a 2 channel signal, the overall sound could be poorer than if you had just gone through the analog ports on the soundcard.
Taking this a step further, if you are up-matrixing a high quality music file that data is sent to the 8 channel DAC on the CMedia chip and it is converted to analog as a 24/96 signal. If you use DD 5.1 then that signal is encoded (lossy process) and it loses a bunch of information. Same goes with DTS (though it is not as lossy and is a higher bitrate). But we still run into the problem of possibly using a poor decoder with crap DAC's. Now, if you have a good quality receiver, this isn't as much of an issue, as the hardware is good. But we still have to address the issue of downsampling and encoding an audio signal to a lossy format. Now, PCM takes care of this, but it is relegated to a 2 channel signal, so no matrixing there.
The best solution to keeping sound as clean and untouched as possible is ASIO along with PCM that matches the file characteristics (bit-accurate). But for most applications, this is not a good solution (games, movies, etc.).
So, don't give up on analog outputs on a soundcard yet! There are still areas where it will sound better.
Just for grins though, I did order up the Burr-Brown/TI OPAMP upgrades for both the X-Mystique and X-Plosion I have here for testing. I should have the initial article up fairly soon (as in the next two days). Just a teaser... it really helped the X-Mystique... but for some reason these upgrades made the X-Plosion just shine.