APPROXIMATE PURCHASE DATE & PRICE: As soon as possible (this week if I can find something that fits my needs.) 600-800$ (Canadian) after taxes, delivery etc... I basically don't want to spend more then 800(Canadian)$ to get it to my house.
SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: MSN, School Works, Gaming (Diablo 3, Starcraft 2 and Warcraft 3(Dota))
PARTS NOT REQUIRED: Keyboard/Mice (I'll just buy some standard 7$ keyboard and mice.
PREFERRED WEBSITE(S) FOR PARTS: Newegg.com but as far as it's cheap and it deliver in Quebec it's fine with me COUNTRY OF ORIGIN: Canada (Quebec)
PARTS PREFERENCES: In the past I've only had Intel processor, Nvidia graphic cards, Corsair memory but I don't mind changing brands.
Random comment: I used to play dota, until I discovered Heroes of Newerth. It's basically a "dota clone" with a new game engine that's more flexible and MUCH better online matchmaking (you can search games by dota options like ap/sd/rd, em or no em, etc.). Unless you're a hardcore competitive dota player who can't accept any changes to dota gameplay, you should check it out. I don't think the open beta has started, but I can get you a beta invite if you'd like - just shoot an email to firstname.lastname@example.org and I'll send you an invite so you can try it out. It's $30 US to pre-order the game which gets you a few minor (non-gameplay affecting) perks and lets you reserve a screen name, if you decide you like it.
Why_Me's build looks good. If you have more room in your budget you could consider a slightly better GPU and display, but the ones he found for you are really great deals at those prices.