We take 401 East, then QEW/403 to the border (Peace Bridge) and then take I90 all the way. We always make a stop at the Angola Service Station for lunch/fuel once across the border. We usually stop before the border for gas, as Angola is still a bit of a drive from the border.

Edit: This is pretty much our exact route: http://goo.gl/maps/0T3XI

Which doesn't include pit stops, of course.