Its tough building a decent gaming computer on that budget. You are probably better off buying a $400-$500 laptop, and those laptops should run WoW smoothly. Here are the minimum system requirements for World of Warcraft: http://us.blizzard.com/support/article.x... Most new computers should be able to run WoW.
I am assuming by build you mean build yourself, if that the case then concentrate your money on the processor RAM, any new dedicated graphics card with 1GB memory should be plenty for WOW. You will also want to get a Ethernet card made for online gaming. I would start with a Intel i7 processor and 4-8GB RAM with a good motherboard and then get the best things your buget can handle after that.
If WOW is the most computer intensive thing you will be doing on the computer, then you won't really need to upgrade. Get a SSD if you plan on doing video/sound/photo editing and a better graphics card or a dual crossfire setup if you want to play modern games like Skyrim.
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.