Ogilvie is on my list due to both its history (it's the oldest elevator currently standing) and the fact that it's about to be torn down. Whether I draw it as it is or as it was, I'm not sure, but the flour mill part would make a pretty nice diagram.
The other elevator I definitely want to draw is Western Grain (
which I've been inside), Saskatchewan Pool 7 (the longest in the world when it was built, and together with units A and B still the largest grain handling facility by total capacity), Saskatchewan Pool 4/5 (4 exploded, 5 is abandoned and is the city's tallest grain elevator at 65m), and possibly Pool 6 as it appeared before its implosion to show off the insides of the silos.
It would be nice to do a diagram of every one, possibly even some of the old wooden ones from the late 1800s.
I'm also planning on doing a diagram for the power plant (including the actual generator building, 72m, not just the stack) and in the future, the Resolute Pulp Mill, since that is the tallest "building" in the city at 74m.
I'm also thinking of following Alpha's lead and drawing the CJSD radio tower on Mount Baldy (tallest antenna in Northern Ontario) and the CKPR radio tower on Hill Street (which is prominent).