There are a few very good artists in Ontario I would recommend.
Bob Paulin did my first tat. He has won countless awards for his realism and whatnot. I swear almost every mag I pick up has him in it. He does absolutely amazing stuff. You can see a lot of his work featured on BME. He sold his first shop to open Sacred Flash in Welland, but since sold it, although he still does tats out of it. It has currently been sold yet again (to Bobby, not to be mistaken for Bob) and everything is being organized and whatnot. I think Bob is still working out of there though. The site has been taken down under the new owner, but the phone number is (905) 714-0010
My new tat artist is Justin from Belmont Lounge in Thorold. He does really sweet work, and it can be viewed on his site at www.belmontlounge.com
I've seen a few people with Jamie Izumi's work as well, and have looked through his portfolio online in the past and he does awesome work as well.