BEagle,
If you want network security, go wired. Limiting MAC addresses does not stop someone from reading your wireless traffic, (since it is not encrypted). But, it keeps honest people from logging on to your Wireless Network.
WEP while having its security issues, does at lease encrypt your data. That along with limiting MAC Addresses, is a little bit more secure but it will not keep advanced hackers out of your network.
Then again, what do most advanced hackers want with someone's home network? They are not looking for a small home network. They, 99.9% of the time, want a business or government network.
Take Care,
Richard