Hyatt Regency, followed by the Delta Mtl.
I've never stayed there, but if i had, i'd probably put Holiday Inn Express between those two. I once visited a friend (a fellow Toronto Blue Jays fan) at that hotel & i must admit i was pleasantly surprised at how nice it looked.
The 3-star hotels i hate the most? No surprise there:
Doubletree (which i call Doublecrap)
Holiday Inn Select
Any of the 'Days Inns'