I use whatever hand is handy for whatever I am doing. (terrible pun, sorry)

I do have prefered hands for particular tasks writing with the right, eating with the left. I can't use a drafting table set up for a right handed person for some reason....even though it seem counter productive, I find it easiest to use the left handed equipment and reach over the stuff with my right.
and the notebook thing...my poor brother was constantly getting notes sent home from the teacher....because he would get to the middle of the notebook, switch hands and keep right on going.