What brand vitamins would you recommend for someone who wants to start imroving their health?

Brand not important. I agree with dr. Ruiz-healy, except that it's very difficult to get sufficient vitamin d from the foods we eat. You should take a daily vitamin d supplement. It doesn't matter much which brand, but vitamin d always must be taken with a little bit of fat or it won't be absorbed.
Reearch. Start improving your health by taking a good look at your nutrition and activity. Vitamins and micronutrients are in nature, in the sunshine, the foods we eat, the water we drink. All this said, i would recommend you look at products that are free of dyes and fillers, a good source to start is: http://www.Multivitaminguide.Org.