FallowEarth yea wep is very insecure and you really shouldn't use it, but some people still have network cards that wont do WPA, and WEP is better then no SSID, and mac filter.
now the reason mac filter and turning off SSID are bad is because of 2 little programs, Cain & Abel, and Ethereal, Cain will find the ssid in a sec and ethereal will give me the mac id of your computer and i can mask my mac id with your mac id in ethereal and then be in your network in less then 30 seconds using your internet and doing what ever and the whole time your router thinks that my computer is actually your computer.
The only true way to secure your wireless network is with WPA. All the other security methods have been broken. I have personally broken every one except WPA.
Someone has a better chance of getting in your network through the internet then they do going through WPA.