With DHCP your IP is dynamic, it doesn't ensure that it will remain the same. Blocking a dynamic IP address isn't a good method. Some home router DHCP service allow you to staticly assign your own address, therefore bypassing the filter and DHCP. Filtering out all IP addresses except for one can still be bypassed by denying the computer with that address and spoofing the address or waiting until that computer is off and using that address.
MAC address can easily be changed or spoofed through the registry, bypassing the MAC filter. Anyone can easily capture MAC address information with Ethereal because of the way the Switch envirnoment operate.
It doesn't mean that everyone is technically savvy to perform all this bypassing technique, however it's still feasible that you apply these security setting. It's better than no security.