Although there is no known results of long term use, creatine is marketed as being perfectly safe to take. If you are looking for a quick way to put on pounds and develop stregnth, I recommend taking Creatine Monohydrate. You have to remember that supplements including creatine will not work unless you are prepared to work. Protein shakes along with multivitamins are popular among bodybuilders, weightlifters and other athletes too. Protein is necessary to build muscle and along with drinking protein shakes, most bodybuilders try to eat as much food with protein content as much as possible.
Multivitamins are a good way to make up for little to no intake of a certain type of vitamin.
People who take multivitamins are rarely sick and are quite healthy. That doesn't mean go out and buy every supplement there is, but taking a couple of different supplements isn't a bad idea.