You could try shopbot to find a few better prices. For instance Windows 7 you could price match a bit cheaper
Microsoft Windows 7 Home Premium OEM 64-Bit - Price Comparison - Canada - Operating Systems. you could also knock 15 bucks off the 3570k etc... I would worry about price matching a bunch of stuff I've never had any problem at memory express.
One question, why the 2.5 HDD? A 3.5" will be cheaper and faster.
Black Friday is not too far away either. Although its tough to build a computer from random parts on sale that sell out in a few minutes, if the site doesnt crash.