Let's see. I grew up in Niagara, and went to school in KW.
I concur that Sharon Okimi at U Quilt it is amazing. So unbelievably awesome.
Greenwood Quiltery in Guelph has an amazing sale on right now, until Jan 10th - $2 fat quarters and fabric as low as $5/metre. Don't know how much they have left (I live in Texas now, and the commute's a bit far) but they only do this kind of sale 2x a year. More modern fabric, but a good selection of kids' stuff, and they have Oliver & S patterns, Kaffe, Amy Butler.
Creative Sisters Sewing in KW is worth a trip as well, especially for their Full Moon Frenzy. The next one is Jan 26, but they do 20% off fabric, 15% on other stuff, and the closeout fabric is usually something along the lines of 40% off. They also do amazing longarming.
Finally, Quilter's Nine Patch in Elmira has a lot of modern stuff, and also a lot of super-traditional stuff (like civil war repro.) They also have Amy Butler and Heather Bailey patterns, among others.
Closer to home, there's Quilter's Dream on Guelph Line in Burlington. They do a lot of classes and retreats and workshops. They do a quilter's cruise, I think, and they have a retreat coming up at the Kittling Ridge hotel in Grimsby.
The other really good, inexpensive, fabric source I had in that area was, believe it or not, IKEA in Burlington. Their as-is department is wonderful for sheets for backing and/or wholecloth, and they do actually sell fabric by the metre - it's near the curtain/pillows department downstairs. Really good prices, and weights in everything from thin and gauzy for art quilting to more heavy home-dec type. Lots of the fabric is about quilting weight.