I do the same thing (although if I do go down the Fon route I'll need to rethink this).
1) I unplug everything when I go to bed. Stops fires (in theory) and is one less thing to worry about
2) Security, turning the internet back in to a sneaker-net. I don't really worry about someone piggy backing my connection (contention is contention).
3) I have something off-line to do. The web is a bloody siren call. Since the router is in the hall and the comouter isn't (the call no place to do any business unless it's shooing a candidate from the doorstep).
4) I'm not using it. Why leave it on? Energy saving and all of that...
tags : router, wireless, safety, security, network, Fon