I will 2nd that a graphics card is almost irrelevant as far as AM is concerned. A budget $100 card from AMD/ATI or Nvidia will work. Either a Radeon 6570 or Nvidia Geforce 640/650 would be good.
I would go with 8GB of RAM, more than that is probably a waste unless you are running virtual machines or scads of programs or plan on doing really high-res photoshop work or HD editing.
If you are on a super budget, you may want to consider an AMD A10 APU-based system, you get a quad-core cpu (although not as fast as Intel's lastest offerings) and discrete-level graphics performance (on the CPU die).
You can get a 128GB SSD for around $75 now. Kingston brand. You may want to consider that for your OS/programs, and get a cheap standard drive for media files.
You could probably put an AMD-based system together for around $500, OS and all.
I would definitely recommend Win 7 64 bit, professional copy. Don't screw around with win 8.