According to al Qaeda documents, the three big targets were Spain, England, and Poland. By that rationale, I'd say Poland. Italy is most certainly an option.
They called for attacks in states allied with America, and a halt to attacks in America. I don't think that will last. I expect something around the time of the next Presidental election. It will be a very important election for them. If they are able to influence us to choose a president that will re-instate Clintonian policies toward terrorism they'll have it made for at least four years. Plenty of time to fall back and get their second wind.