Among APs I detect, the secured:unsecured ratio is:

Add to this, that some (possibly all?) of the routers provided by Verizon only support WEP encryption... and suddenly, turning off wireless on that router and setting up a secondary wireless router (one which supports WPA2, of course) on your network in "bridged" mode, starts to sound like a really-really-good idea.

Depends on the router. My router has an optional guest mode. When using the guest connection, they are put on an entirely different subnet so they can access the internet, but not access my personal network. Works great. You can have a secured normal access point that you use for the computers in your house, and then when people come over and want to use the internet, give them the password to the guest internet, and you don't have to worry about giving out your secure password.

Monitor the network long enough to collect a bunch of the allowed MACs, then use one that doesn't seem to be on at the moment.