AnakinGuy12 :
My problem is that I need a new GFX card also. Probably a 7850 or a 7870. So I was saving up for that. (That's not a cheap upgrade). So which do you the think I should upgrade first, GFX card or RAM? (I know I'm getting off topic, I'm sorry.
As I (and others) said, 8GB is enough for just about everything most people do. You already have your existing system, you can simply try doing everything you expect to be doing and see if your performance gets hindered by lack of RAM and add RAM if it turns out to be necessary.
The main reason I have 16GB RAM is because I have a bunch of programs that I tend to leave open all the time and I need about 10GB of disk cache to stop them from accessing the HDD all the time - on my previous PC with 8GB RAM, I had to run each program from separate HDDs to prevent HDD accesses from obliterating performance. If you run only one large program at a time, you shouldn't have that problem unless you do some very fancy stuff in Photoshop or Vegas.
Some people do not like skimping on CPU, others on GPU, others on other stuff. For me, it is RAM: having enough of it to eliminate swapping and reloading makes my computers more pleasant to me than having faster components. All my PCs since my P200MMX/256MB have been maxed-out on RAM.