WEP = is very crackable at the moment
WPA/WPA2 = is crackable, but harder generally and not known as well
Mac Filtering = useful, but limited, because its not that hard to steal and then spoof someones Mac to get on the internet.
VPN is the most secure at the moment.
Other technologies that WAPs employ is Radius Authentication with a Captive Portal. This makes users login before they can gain access to the internet/network. Not like VPN where you appear on the otherside of the firewall, with this the firewall opens up to you. This is more common at public WAPs that you have to pay for.
Both of my WAPs are completely unencrypted and on seperate networks from my main network. I then use VPN to gain access to my network from the outside, from there I can use any resource on my network, although I have more security features, like Captive Portal and Proxy running.
I find WEP and WPA can be a real sod unless you have really expensive hardware. So i simply just don't use them.
Also its fun to see people appear on the WLAN and try and get the interent, they usually last 5 mins before they give up.