Most of the time I work with Gnome, which comes with a network manager. I was never really happy with it when it comes to wireless networks since its configuration appeared always somewhat unpredictable to me. After a fresh install of Ubuntu Hardy Heron on an older laptop having a NetGear WG511v1 wireless card, the network manager did not even show the available networks anymore, and it forgot a configuration each time a different network was accessed. But then I came across a great and much better alternative to the gnome network manager - wicd. It does exactly what I expect from a network manager, like listing all available networks including signal strength and encryption mode, configuration is easy, etc. Great!