Why the heck do some people do it before? Food tastes nasty and especially OJ, as has been mentioned before. I mean the point is to clean your teeth, not clean your teeth and promptly get food all over them.
"Brush your teeth after every meal." After is the correct answer, sorry guys.
By the way, get an automatic toothbrush. You'll love it. If you don't brush often, an automatic will get you brushing.