I use mac filtering to ensure only devices that I want can access the bandwidth.
Does that mean you only use mac filtering and no kind of wireless security? If so, you are overestimating the security that mac filtering provides. It is very very easy to clone your mac and get by this security. As for a incompatibility with vista, Vista does add other mac addresses for different adapters and connections. Also, Vista uses IPv6 by default and this router is compatible with IPv6.
1. Make sure the Mac Filter is set to: "Turn Mac Filtering ON and ALLOW Computers..."
2. Mac Filtering should be secondary to a good wireless security.
3. Make sure your adding the mac address of the wireless adapter. Not the LAN. The LAN is not being used if wireless.
4. Turn off IPv6 on the IP Stack Start>Run>NCPA.CPL> Right Click Wireless Connection + Properties > Uncheck IPv6