One that's always caught my eye but I know very little of is the domed section of Manulife on St Paul's Sq. Seems really neat, also the one to its north I'm noticing now too. There's probably a dozen more bldgs that I'm forgetting but this one thought could use a mention here.
And Leaside Towers has always been really pronounced just for how bloody large and monolithic they are. Thorncliffe area has a classic modern suburban style that has its charms.