Colossus is the best Greek restaurant west of the danforth. It's portions are generous and the cooks do a good job of maintaining consistency over time. I have been here many times and am amazed by at how good it always is.
Good options are the saganaki, seafood platter or seafood salad, as well as the lamb.
The souvlaki is also good but I tend to pass on it because the other stuff is more exotic.
Service is also good although it can get busy on weekend nights even with a reservation so it is not uncommon to have to wait 10-15 minutes for your table to be ready.