According to this article, it seems like WEP secured WiFi networks are not so secure at all... finally.
Most security mechanisms are safe until they are not safe anymore. But for the time being, one should rely on WPA2 for securing a WiFi network. Even more specifically at home.
I remember commuting by train with a laptop on my knees, trying to fix a bug in my source code. I did not notice but found my WiFi antenna was on. I was impressed to see so many WiFi networks popping-up on my radar screen as the train was rolling towards downtown. I would say about 50% of the networks were not secured at all.
Later on, I will try to tell more about this, even if I am not a network specialist. But for now, I just wanted to point this out.