I reckon Montreal would have a much more impressive skyline if it wasn't for the hill (height restrictions notwithstanding). The hill can cause a lot of downtown's density to blend into the landscape, a particularly bad example of this being the photo posted by MTLSkyline last page:
Silo 5 by
Charles-Antoine Vézina, on Flickr
Take the hill out of the picture and you get FrAnKs' photo at the top of this page which looks like an entirely different city