A.W.
K.,
This is a really touchy subject for a lot of people....and hopefully I don't get flamed. :)
I think that there is a bit of hysteria surrounding immunizations; you can find articles and statistics to support both sides, and ardent supporters of both sides.
However, to me, I think it's responsible to vaccine against these sorts of communicable diseases to prevent the thousands of deaths that would be caused without the vaccine. Without the vaccines, these diseases will reappear and become rampant again. It's a difficult debate, but I think the benefit (social protection against disease) outweighs the risk that has yet to be firmly established (I'm not saying it isn't there, however).
At the end of the day, you have to do what feels right to you for your child. I worry, though, that if enough parents stop vaccinating -- how many children will be put at risk for the epidemics that will arise?