If I lived in a large European city, I'd be more concerned about Muslims than I am living in New York. At least they assimilate somewhat better here, although we've have had some homegrown terrorists in the U.S., as well.

When they are very isolated, by choice or otherwise, they're going to be resentful toward the general population outside of their communities. Dealing with it is just as important as foreign policy, if not more. We have mosques right next door to Jewish synagogues, and there's no problems for the most part between the two groups.