I remember reading an opinion piece a while back, prior to the Egypt protests. The thrust was that, in this area of the world, the US is in a tough spot. We have authoritarian governments who are at least notionally friendly to our interests...but we also support democracy. And the fear for a long time has been that one of these countries, with the huge influence that Islam has on the culture, will elect religious leadership. Perhaps even radical Islamic leadership. Which is not friendly to US interests.
Do I personally believe that is what's happening in Egypt? I don't know. I'm not a foreign policy expert. I do wonder, though, between Egypt and Tunisia, is this just the start of something that will sweep across Northern Africa and the gulf? The Saudis are already saying the protesters in Egypt are plants to undermine the faith in the Saudi government. Probably about as believable as Israel dumping sharks in Egypt's tourist hot spots, but it does speak to the fear other governments in the region have. The protests are already destabilizing the regional economy...Saudi's stock exchange has dropped more than 6% since the protests started.
It'll be interesting to watch it play out. Hopefully it can get resolved without too much additional violence.