I think the chickenpox vaccine should be optional. The HPV vaccine (Gardasil) should be optional and offered to both sexes, not just females. I don't really have an opinion about some of the others, like hepatitis, meningitis, and pneumonia.
Measles, polio, tetanus, pertussis, diphtheria, and a few others (like smallpox if it ever gets going again) should be mandatory.