I say "go". Since the 1980's every time there has been a terrorist scare anywhere on the world, people in the U.S. wondered if it was still safe to go to Europe. It happened during the Gulf War, after the first WTC bombing, after the bombings of U.S. Embassies in Africa, etc. I have seen these scares come and go, and as far as I know not one single U.S. tourist in Europe was the victim of a terrorist incident during or after the crisis period. Go, and have a great time!