Id get at least a 1TB HDD, the price is hardly any different as you pointed out and it will last. (Personally I no longer buy new HDDs smaller then 1TB anymore.)
About your cpu. Again it depends on your needs but the FX-6300 will likely handle anything you will throw at it. Are you doing any CPU intensive tasks such as compiling very large programs, computing math problems, solving algorithms, or running any CAD software? If you answered no to all those then the FX-6300 is a great CPU for you, it can handle games and daily "multi-tasking" computer work. Personally I think the FX-6300 CPU sold by AMD is a great choice, most people dont NEED 8 cores and a $150+ processor.