Looking For A Good PC....?

I'm Looking For A Fast PC, Not Mac... Umm... I want it To Be Good For Gaming Eg High Res, Fast Speeds Etc.. But I Want It so I Can Add Or Modify it Whenever I Want and I'll Use It For Occasional Internet Browsing.. Looking For Something �500 or maybe A Little Bit Over? Nothing Under As I Don't Want Some Really Crappy One, So Over all... A Gaming Computer Around �500 Thats Fully Customizable... Any Ideas People? "/