Toronto is such a big city -- it actually depends on where you are in the city, really.
If you're downtown, Hy's is really good, Barberian's is not bad either, Harbour 60 is the best but most expensive. My only thing with Ruth's Chris and Morton's is that they are franchises of US chains -- so there is less value in my opinion.
If you're into steak, there's 2 others I recommend:
La Castile -- Dundas/427 area
Duncan House -- Don Mills/401 area
Someone mentioned the Pearl which is great for Chinese with a view of the water. I agree.
There's really good choices for Mediterranean, Italian, European. Best to find what your customers are into.
If you're going downtown, only one place I know of where people are suckered once into going because of the attraction -- Captain John's. Cool that it's a big old huge yacht, but the food actually sucks and it's not exactly cheap.