NCIX is good, they actually have a location opening in Markham, ON tomorrow so now we won't get hit with heavy shipping costs from BC.
Also, I must recommend
http://www.filtechcomputer.c om/ . It's a small computer store at Spadina/College in Toronto. They generally have the lowest priced components, you can buy all your parts and they will assemble it for you. Their website usually has the lowest prices even when it's not updated, but sometimes you can get even cheaper prices once you submit your quote to them. Also, there is the rare occasion I can find a component cheaper elsewhere and they have matched it for me. My last two desktops have been from there, and I haven't had any problems.