Good selection of Cascade yarns.
Lettuce Knit is my favourite store in the city. Good selection of yarns that you might not find elsewhere - Socks that Rock, Blue Sky Alpacas, Fleece Artist/Handmaiden, Lorna's Laces. Friendly staff and they offer great classes too.
Check out their website for sales! Stocks Brown Sheep, Fleece Artist. Great selection of books and magazines.
Not too bad for a mall store. They do carry a lot of patons and Mary Maxim yarns, but also have some Noro, Cascade 220, Lang Tosca. Small selection of sock yarn.