There is opportunity here...

Let's for a minute assume the Mubarak regime is doomed. This isn't a stretch...

Without even considering who takes control of the government, I think several possibilities present themselves in the region that might even be GOOD for the US.

1) Many regimes in Arab countries that have traditionally been closer to the US than anyone else in the last 25 years will have to pay very close attention to keeping those relations strong. In the case of Turkey and Jordan, this is especially true. Both will have to begin implementing changes NOW to avoid this sort of riotous action later... and that means coming to grips with anti-Israeli elements within their countries. Association with American interests in the region means association with Israel, in one form or another... and in maintaining those associations, which can only benefit all involved, the "people" see the actual benefits quicker than not.

2) Israel is going to be "forced" to work with the PA on a level not seen previously. This does not mean the PA will cooperate (although I think the Fatah-faction will) with Israel, but it does mean that issues that tend to be pretty one-sided in Israel (settlement construction, embargoes, road and rail closures, worker transit issues, etc) will be back on the table so that there is less to feed the fires already smoldering all around Israel's borders.

3) Europe is going to be "forced" to recognize Israeli reality versus European daydreaming, or face the consequences of seeing what has happened in Tunisia and Egypt happen again in Turkey, bringing the very real possibility of radical Islamic leadership to the very doors of Europe itself. Unrealistic expectations and gross hyperbole on the part of European leadership in regards to Israel policies towards the PA will simply have to be tempered, or the unrest will be fed in a country that can directly effect European security on a daily basis... and that can't possibly be a "good thing" given the growing numbers of Muslims living in Central Europe.

I do not deny that exactly the opposite of what I am suggesting here is more than possible... but if it should occur, then the worst possible scenario will already have begun to unfold. Leadership across the region (even globally) will have to drastically change, or this sort of unrest and uprising will spread like a plague across the Muslim world. This is the product that repressive, mono-chromatic regimes produce: radical reaction to authoritarian leadership when no popular opinion is able to be considered. The result however, is not always "good" either... the selection, even by democratic, popular means, of another repressive radical regime of the opposite view.

I find it terribly difficult to imagine any Western state intervening in the Egyptian crisis right now. Aid, support, calls for peaceful discussion, are all possible... but they are unlikely to produce anything substantially smoother in the area of transition than is likely to come from any other effort at all.