Kaji.
Best in Toronto hands down. Just don't go there expecting rolls and shit like that. Kaji is hard core, traditional Japanese food.
Following that:
Blowfish - come out and see the beautiful people. I recommend the Ebi Shooter. It's great.
Following that:
Sushi Couture on Bloor, just east of Bathurst
Following that:
Hiro on King around Jarvis.
Edit to add:
I've read about Hashimoto being the complete sushi lover's paradise. Not only do they only serve I believe about 12 people per night, they serve you in some sort of traditional Japanese fashion. (Sorry, I forgot the name.) They are located in the Japanese Cultural Centre.
I have never been because it's priced at $300.00 per person which to me is just too over the top. (Unless it comes with a 95 pound Japanese geisha under the table performing oral sex on me between courses.)