The BCC reports that British Telecom uses WEP on its home networks: I'm not sure whether BT enables WEP by default on their home Wi-Fi routers, or if you can't upgrade to use WPA or WPA2 at all. However, this makes the WEP crack that will be discussed by AirTight researchers at ToorCon this weekend all the worse. I tend to think of WEP as so 20th century--something used only in despair. In fact, this BBC article makes clear that WEP is still in wide circulation because of compatibility issues.
I think of Windows XP as the default operating system for Windows users; there are still plenty of pre-XP home users out there, too. (WPA can be used on some pre-XP systems, depending on drivers and other factors.) The other day, a colleague received email from a graphic designer who uses Mac OS 8.6 and is still happy with it, but is considering updating. That's a nearly decade-old system release. I suppose I'm too sanguine about WEP's availability.