I've experimented with various brands and quality multis, the cheap ones like centrum made me sick, like every time I took them for a couple of weeks it seemed that they weakened my immune system and I'd get a sore throat, sometimes fever. Happened EVERY time with the cheap multis.
The expensive ones didn't give me any trouble but they also did nothing for me (at least as far as I could tell).
Same as Moonblaze, I stopped quite some time ago and never looked back. I understand that it sounds kinda appealing to have that safety net that contains everything we need but IMHO it doesn't work that way at all. We just haven't figured out enough to throw some arbitrary stuff into a pill and think it has the same effect as the stuff mother nature created.
Moreover, I do not believe that for optimal health, it is necessary to hit 100% or more of the (human made) RDA every single day. The body is quite capable of regulating itself and I think it's kinda crazy to take those insane amounts of vitamins.
With real food you'll get one day a bit more of this and the next day a bit more of that but in the end it all works out if you eat a good variety of real food :)
Also, I think worrying about all the differnt ingredients that could be bad for you in the multi is too much trouble to bother. folic acid vs folate, b12 as crappy Cyanocobalamin, crappy c and a forms (http://suppversity.blogspot.com/2011/10/are-there-pro-oxidant-cytotoxic-and-dna.html),.............................. do not want ;)