Nick White, from Micorsoft's Vista launch team, has posted information about the new audio features on the team blog. The features include: loudness equalization, forward and reverse bass management, speaker fill, and room correction.
For input, there's microphone array technology, where having (say) four microphones built into a laptop provides good results without you having to use a headset. This would be useful for voice calls and conferences, and speech recognition.
Ars Technica has a summary.
