I could be wrong, but in my opinion the only thing that IQ has really proven is its ability to predict how well a person will do in school. I doubt it really does much for predicting titans of industry (or some other area) and success in general.
I think its main flaw is that in general, life isn't constrained to a limited set of multiple choice answers; it's a lot more open ended and chaotic. Not to mention that some of the questions used to administer these tests are biased... and o yeah, there are also different types of intelligence...
(Yes I have a high IQ, and high scores of other major ancient traditional testing methods.)
IQ or the way it's currently administered is just too archaic, limited, and just outdated. It needs to change.