There is no point in hiding the SSID at all except to stop the average user from connecting to your unsecured network. Anyone wanting to use the network can discover the SSID very quickly in seconds.
But if you want to stop people using your network, it does not make sense to leave it unsecured in the first place.
There is also no point in using WEP - it can be hacked in seconds. Literally. So why bother?
WPA is fairly safe, but again, why bother when you can use WPA2?
WPA2 is safe at the moment, so use it.
If you have WPA2, there is no need to filter a MAC address. It is not possible to get into the network without the key anyway.
So those that say that it is fine to use WEP, but then suggest to hide the SSID and filter the MAC address - this is not good advice, unless no WPA or WPA2 is available.
Virtually all devices are able to use WPA2 now, sometimes a firmware upgrade is necessary, though.
Regarding public hotspots, remember that anything non-encrypted (e.g. not https) you do can be intercepted by anyone in range. So use those hotspots with care. And always use a firewall when using a public hotspot!
Regarding the "Free Public Wifi" - these are not access points, but ad-hoc networks, which you can recognise from the different symbol. Never connect to an ad-hoc network that is not yours. I believe the default is that you will continue offering this network to others until you remove it. So these "networks" are a bit like viruses in that they spread from computer to computer.