Hell NO I don't favor an internet "off switch". If the government wants to keep it's networks safe from cyber attacks then let the Government Networks have THEIR OWN "off switch" to cut themselves off from the rest of the internet. If you ask me the only reason the government would want to have an internet off switch would be to keep the people of any given country from reporting what's really going on in that country to the rest of the world. If you control the flow of information/news then you control a lot of power, as we all know information is power.
For instance, if the government of Egypt decided it wanted to start murdering it's people en-mass or murder a certain ethnic group without the world finding out, here's what they would do...
1. Close the Borders. No-one in, no-one out. This would especially include people from foreign news agencies.
2. Control the Local Media. The news agencies in their own country will broadcast what-ever the government tells them to. Either they say what they're told or they lose their jobs...and possibly lives.
3. Shut Down All Communications. This includes jamming short-wave radio signals such as CB's and local broadcast towers. Shutting down or cutting off satellite and cell phone communications. This also includes The Internet.
Now they can freely mass murder who-ever they want, get any type of situation under control, and then when the dust settles they turn everything back on and feed the world what-ever bull sh!t story they cook up to explain what happened. Like maybe a new bio-terrorist attack with a new genetically designed plague that only targeted people with certain genes, such as those specific to a certain ethnic group.
I know the part there about the "genetic plague" sounds a little unrealistic and they'd probably think up a more logical excuse, but, from the advances in genetic manipulation we're making which is growing in leaps and bounds, viruses that could target only curtain races aren't necessarily that far off. There are already certain diseases that are race specific in the world. The only one I can really think of off the top of my head would be sickle cell anemia which to my knowledge only affects people with African heritage. Imagine though if something like that was manipulated until it turned into the next bubonic plague.
Analysts have already been talking about and planning for the first major "Bio-Terrorism Attack" for a while now with things like Anthrax and such. Honestly though, if some kind of "genetically advanced diseases" or "super-virus" were to hit us the first people I'd be looking at to blame would be our own government. To my knowledge the only two countries who's scientists are close to actually being able to do something like that are us and Japan and I don't see why the Japanese would want to hit us.
Aside from all that, there's plenty of other ways for the government to protect themselves from a cyber attack than by taking my internet away during an emergency. They can take their own networks and cut them off from the internet, as can important companies with sensitive information in their systems like military contractors. Not to mention that during such an attack, there could be plenty of people in the US who would be fighting back from their own home systems trying to attack the attackers. I know I for one have curtain...software...that if I detect an intrusion into my network I can trace it back and seriously mess up the person who's hacking my system...if I wanted to. Why would the government take people off-line who could be virtual cyber soldiers for them? There are plenty of great American hackers here who would gladly help serve their country in a situation like that, but without the internet they can't be of any help. It would be like taking a soldier's gun during a fight. I'd say that's a bad idea.