Although almost expected as part of Vista, it seems more a the behest of the industry than per Microsoft itself that the integrated firewall of the new OS will be crippled. Although, by “crippled”, it's really functioning quite similar to how the existing Windows firewall works, in that it will only filter inbound traffic and not outbound traffic. Very useful to prevent worms/trojans from spreading via remote exploits and from external intrusion, no outbound filtering makes it easier for existing trojans to propagate themselves or for unwanted software to run.
The functionality isn't completely removed, however, and the ability to filter outbound traffic should you need to is available, provided you have the “technical knowledge” on how to do so. Although in a perfect world, traffic shaping occurs outside of the workstation, many companies still do use per-machine firewalls to some degree. As for home users, this will impact them little if at all, and of course there are also other firewalls to choose from.