Multivitamins are at best, not necessary and at worst, detrimental to health. Simply consume a diet consisting of whole and minimally processed foods that are micro-nutrient dense and you should be fine.
There are many studies which actually support the theory that multi vitamins increase all cause mortality.
For those that like to read, there was a long discussion on the topic, replete with sources here:
http://forum.bodybuilding.com/showth...hp?t=135381541