In the long run, if Tunisia's authoritarian dictatorship is replaced by a more open and democratic government, and if something similar happens in Egypt, that will probably lead to greater stability and security for everyone. Unfortunately, this is one of those long runs in which many of us are dead. In the short term, riots and protests in Egypt, and the anticipation that they could lead to the fall of one or more Middle Eastern regimes, lead to [stock market turmoil.
Obviously, we should all be warily celebrating the possible fall of the Mubarak regime, not bemoaning it. Not because it will lead to any near-term benefits for us, but because it stands a chance of making Egyptians freer.
That doesn't mean that such freedom will be in the interests of the United States, in the near term or really in any term we can envision. We should be cheered when other nations start to "find their voice", not because it is in our interests, but despite the fact that it may not be.
Again, there are time horizons differences here. For example, FLG can envision a future where democratic governance does, in fact, coincide with the United States' long-term interests. But those are nitpick points.