I've always attempted to sit in the back row or just anywhere not in the front. If i'm in the back row I can lean back and stretch or move while not having somebody yelling at me for leaning over their desk or being in their way and by not being in the front I can use the basket of the desk in front of me as a foot rest. So it's just more comfortable and less disruptive in my opinion. That and the fact that I can usually see better at a non-close up distance.

For some reason the more studious students take the back seats in classes at my school. Then again I guess that would force the more troublesome students to be by the teacher which might make them quieter.... interesting concept.