If you are like me, and want to be able to call someone to solve a specific problem, and you want easy-to-use stock screens, then consider:
1) Schwab
2) TD Ameritrade. (It is Canadian, even though it expanded to the States years ago.)
If you don't mind a complicated stock screen, and want even cheaper commissions, then go to Interactive Brokers. I think they will allow you to open an account from Canada.