The firewall in the original release of Windows XP was adequate, but really left a lot to be desired. But over the years, the Windows Firewall has received a number of makeovers and continual refinements.
By the time Windows Vista was released, the firewall had beenredesigned and was quite impressive. Then the update that came with the recent release of Windows Vista SP1 added even more powerful features--support for Network Access Protection, reliability enhancements, new encryption-related algorithms, and so on.
Full Article - http://blogs.technet.com/tnmag/archive/2008/05/29/managing-the-windows-vista-firewall.aspx