Um, no. I'm running 4GB, Mak is running 3GB. We both run just perfectly fine. I'm using up 1.4GB with ~60 processes running.
It depends on the games you're running. And remember, Win7 still uses SuperFetch which preloads programs into RAM, and dumps them as the system needs RAM.
Guarantee you're never gonna use 8GB of RAM unless you're doing CAD work.
The requirements won't change much, if at all. THey haven't changed from the Beta to the RC with all teh tweaks that have been done and its pretty much ready to release now. And it is a small OS; Win7 Ultimate with quite a few of my basic programs I use a lot, as well as some downloaded things, I'm using up 17.7GB (including a 4GB of virtual memory). Much better than Vista.