http://www.youtube.com/watch?v=rQOvQUiy3-s
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A lot of white balance issues can also be easily corrected in post, but getting it right in camera does really help! Something like the "Magic Filter" can be great, as well.
You will be happy to hear that I correct 99% of my shots in post, but the footage has to be as good as possible when it comes out of the camera. If the colors are completely off you also don't make a master shot out of it in post. I personally don't use any magic/color correcting filters.