I know why MS have turned TCP IP v6 on by default in Vista and Server 2008, I just don’t use it and don’t need it turned on – it makes ipconfig really messy. You can’t uninstall it, and even de-selecting it in the NIC properites leaves it there, but you can disable the tunnelling interfaces that pop up in ipconfig, or even disable it completely.

This article just about says it all http://www.mydigitallife.info/2007/09/09/disable-and-turn-off-ipv6-support-in-vista/, but just to jog my memory all that’s needed is to add the ‘DisabledComponents’ entry to HKLM\SYSTEM\CurrentControlSet\Services\Tcpip6\Parameters and set it to 1.