Comment 1 for bug 118439

Thank you for your report and helping to make Ubuntu better. In the latest 7.10 Gutsy Gibbon release you can disable roaming mode and manually configure your wireless connection to a specific network. This should resolve your first item you listed. Also, as far as I know, if you have connected to a network previously, it will try to connect to it again. This sort of addresses your second item. As far as blacklisting certain networks, I'm unaware of this capability. I'll leave this for the network-manager team to address. Thanks!