I think everyone here generally has the right point of view. "Some people are just stupid no matter what drugs they have or haven't taken." I see the whole spectrum in my own small circle of friends, some are a bit dim and fall into the cliche "pothead" catagory, some are right in the middle and some are quite brilliant despite a lack of classical education. I consider myself to be of at least above average inteligence and even though I smoke pretty much every day, I still find myself drawn to itelectual persuits, often more so while stoned.
If someone is smart and motivated to learn then a little weed now and again isn't going to make any real difference.