Building a gaming PC for 500$ or less

Approximate Purchase Date: (sometime this month or next month)

Budget Range: (>500) After Rebates

System Usage from Most to Least Important: (gaming specifically for guild wars 2 )

Parts Not Required:

Preferred Website(s) for Parts: (e.g.: newegg.com, ncix.com -- to show us selection & pricing)

Country: ( USA)

Parts Preferences: by brand or type (e.g.: I would like to use an AMD CPU & Biostar mobo with a 24" LCD and full tower case)

Overclocking: No

SLI or Crossfire: Maybe

Monitor Resolution: (e.g.: 1024x768, 1280x1024, 1440x900, 1600x1200, 1680x1050, 1920x1080, 1920x1200)??

Additional Comments: (need windows 7 preferred )

Ok here is the thing I am new to the pc gaming scene for the most part and am primarily a console gamer however guild wars 2 looks sick and I would love to play it when it comes out. Problem is all I have is a laptop that is not strong enough to run it. So what I need is a pc that will run guild wars 2 for me at decent resolution and performance I don't want to be lagging all over the place. I don't need to play it top specs though. Also I'm probably going to continue to play console primarily so this not going to be my primary platform for gaming. I don't care about over clocking or anything like that purely out of the box gaming. A plus would be to play whitcher 2 at medium but that is a secondary goal as I can play that on console. On a separate note would I be better off buying a desktop at best buy or something? I need the works mouse keyboard monitor. I would love not to have to spend 500$ and 300$ would be the sweet spot. Perhaps I am asking the impossible, but that is why I am here to submit to your wisdom gentlemen.