If you have been following the NY Real Estate market recently, you've definitely heard a lot about European buyers coming in and buying everything at a great bargain due to the Euro/Dollar spread.
Sales have been slowing in the "mid priced" range of apartments (600k-1.2 mil) but apartments have been selling briskly above the million mark due to a lot of foreign investment.
However, if European buyers start getting cold feet, coupled with reduced Wall St. bonuses and layoffs that could begin the bursting of the bubble.
Here is a link to the article on European buyers. The beginning of the end of the New York Real Estate Bubble?