What's the best gaming/school work computer I can buy with 1000-1700$?

Well, I'm trying to buy a computer that can handle long gaming hours, such as playing World of Warcraft or Crysis, and can also be essential for school work and such. I have a budget of around 1000-1700$ and I was leaning towards the XPS 420 from dell, but I believe its overpriced. If anyone can find a computer that I can buy in Toronto that is better or cheaper than the XPS, with better or the same specs can you tell me? Thanks. :)