From whatswithjeff.com: "One of the most common questions ask by a consumer/user before buying or upgrading their PC/Desktop or Laptop is “how much memory do I need for my PC or Laptop?” “Should I get a 4GB, 8GB, 16GB of RAM or even higher? Before you go off buying a memory or upgrading your system below are some guides or tips when it comes to how much RAM or memory do you really need for your computer this 2013?"
8Gb if your a Gamer
16Gb+ if your working with maya, video editting etc...
Not to mention a total waste of money.