PSU - A 850w power supply is overkill unless you are planning on running dual GPUs down the road. A 650w is fine for a single GPU.
MEM - 16GB of memory? Doing anything special that needs that much memory?
I eventually plan on SLI'ing 580's but until a game comes out that demands the GPU power I will wait and ....yeah I was thinking 8 GB may do just fine. I only use it for Gaming and occasional video editting using SONY Vegas.