I have one question a what if.
What if someone hacked into an electric company and got luck and turned off lights(is that even possible) how long before we could get the lights back on?
If is was software-only, server-disabling, stuff like that, no worries. Reboot, restore, plug the security hole, and you are on your merry way.
If the hacking went on to destroy equipment through malicious software control, then there might be an issue.
Very interestingly, and pinging usc and TM to it, as I was posting this, I was probed. I have a pretty secure home setup. I think the Norks are watching even this thread.