CNet wrote some nice words about Windows Vista, especially the QoS work:

Networking
Windows Vista will come with a completely reworked networking stack. The next-generation TCP/IP stack will work with IPv4 and IPv6, and will also support auto-tuning and quality-of-service features. Wireless traffic will receive numerous boosts in technology to better accommodate for lost packets, bad signals, and large amounts of electromagnetic interference. All these features boil down to better, more-consistent transfer rates for your existing Internet connection.

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Quality-of-service (QoS) features will provide for improved audio and video streaming from local and remote servers. A subset of the QoS modules called qWAVE (Quality Windows Audio/Video Experience) will give priority to audio and video packets, while at the same time monitoring the network's changing conditions to adjust bandwidth usage dynamically. Microsoft is also working on off-network media playback quality. If you launch a new program while playing a media file, Vista promises seamless playback without any video or audio hiccups thanks to smarter resource allocation.