I have been taking vitamins my entire life. My family just always have. I am taking a multivitamin that my doctor told me to take (my grandmother, mother, sister, and cousins all use it too.) In my opinion it's one of the best. It's the "NOW" brand, and it's called Special One. You can't find it in markets though, just in health food stores. I take it twice a day (one in morning, one at night) per my doctor's orders, and I started feeling the benefits from it almost immediately.
It has green superfoods in it and antioxidant protection. No stomach pain either.
(On top of this, with permission from my doctor I take a full tablespoon of Black Strap Molasses once a day for extra iron, it is the most vile stuff ever but really helps!)