You've decided you should be taking a multivitamin. Whatever your reason, when you arrive at the drugstore you're inundated by shelf upon shelf of vitamins, from the generic and store brands to a variety of brand name products. However do you decide.

Health Castle.com suggests:

The #1 thing to look for when choosing a Multivitamin
In order to choose a multivitamin that meets your needs, you should look for a formula that is gender-appropriate and age-appropriate. Nutritional needs for women are quite different from those of men. On the same token, nutritional needs for people over 50 are very different from those of younger adults.

Medrants.com takes this a step further. They examined various brands and picked the best using this as on of the criteria:

None of the supplements we saw are perfect, but our Best Bets contain each of the following: Vitamin A, the B vitamin group (thiamin, riboflavin, niacin, B-6, B-12, folic acid, biotin and pantothenic acid), Vitamin C, Vitamin D, Vitamin E, Vitamin K, calcium, chromium, copper, iodine, iron (for women), magnesium, manganese, molybdenum, selenium and zinc.