Again on Security Incite, Mike says that there is no need for personal firewalls anymore, as the one provided by the OS seems to be enough for most cases. I agree with him when he says that where it is not enough you'll need it from a bundle of other things, like AV and AntiSpyware. I believe we will start to see products like "endpoint security solution".
The AVs are already doing anti-spyware, the personal firewalls are doing some AV, and so on. In a near future every desktop protection product will do all this stuff, protect against "malware" and external attacks.
Corporate editions will also include NAC/NAP integration. There is no sense on installing dozens of agents to keep bad thing out, just choose a single good one to do all the job. It's also a good market trend for the companies looking for ways to survive, include all security features in a single agent and sell it as "endpoint security agent". Nice.