Okay, time to state some opinions....Atlanta's skyline is closer to Toronto than either Montreal or Calgary.

Taken from the west side of Atlanta you'll see that the skyline stretches down Peachtree St. north to south much like the north south spread of Yonge St.
It has a northern hub ( Bloor), a midtown hub (Aura), and a main cluster to the south. (CBD) The largest chunk of towers is in the old part of downtown (south), and the new developments are filling in to the north.
Atlanta's height is also a good point of comparison to Toronto, with 1 000 ft, Nations bank (FCP) then about 7 or 8 700 ft+ towers much like Toronto. Toronto is far denser and has much more built up out lying areas but even there Buckhead would be comparable to the Hullmark/Gibson square area? taken from the west, and once Bloor and Aura are finished the two silhouetted outlines would be quite similar, and a skyline with 4 600 ft towers(Montreal), in one tiny area is a poor comparison. Toronto's skyline is better and with the rash of new condos....will leave Atlanta in the dust. But Atlanta does have 4 towers that kick ass, and would look great in Toronto.