You should go, but don't engage in slogan-chanting like BOMB TEXAS and the other funny things that some people take a little too seriously. Actually, well-attended protests around the world will probably embolden Saddam, make him lean more in the direction of "I can stay in power!", and thus probably lead to a more decisive outcome (namely, military action) than bolloxing around with inspections for the next eighteen months, so attending will be good for the pro- AND anti-war people?