In general, dangers depend on...
In general, dangers depend on the political atmosphere and are usually exaggerated. During high tension periods (read a paper, or watch CNN), there are specific areas that should be avoided. Most of the violence over the past few years has been in the West Bank and Gaza. In Israel proper, it is usually quite, although lately there have been some attacks in city centers. I wouldn't hang out too much in the center of Jerusalem (Ben-Yehuda St.), since that tends to be a target for terrorists. On the other hand, 99.99% of the time, it's quite, peaceful and crawling with police. In general, Israel is not as dangerous as it's made out to be. Drive by shootings are still more common in Los Angeles.
