Okay, since I require some form of sound to work at home I installed Realtek AC'97 drivers for Vista for the SoundMax onboard sound on my ASUS board. Foobar seems to run fine on Vista, which was a nice surprise. However, the onboard S/PDIF out running into my D02 sounds like an elephant pooped a submarine. It sounds reminisent of running something other than 44100 into the D02 (which typically either doesn't work at all or causes distortion, pops and clicks). However, the sound is much much worse than that. There is some kind of disgusting reverb-ish distortion. Sounds like the music is being projected out of a rusty soup can while being crushed by an elephant pooping out a submarine.
I tried connecting my Beyer 250-80s directly into the onboard card's output and the sound, while still pretty awful, just sounds normal awful, not Vistafied awful. Actually I am still getting pops, they just aren't as pronounced. Maybe this is worse than normal awful.
At least I can work now, but I certainly can't listen to music this way. I believe Creative will be releasing E-MU drivers for Vista sometime between now and 2009. Sweet relief is on the way!
EDIT: Vista was also able to install the SoundMax chip automatically, but I had results similar to using the Realtek drivers.