OK is the OS you have installed on another system right now? I also have been playing with WIn8 and it actually has been the only OS I am using at this time. My XP and Win7 partitions I have not used since the Win8 preview was released. I like it for the most part.
Budget is a G, but I wont need a HDD, Graphics Card or OS since I have those items already. I'm using Win7 x64 since I'll have 8GB of RAM but the potential to go up to 32GB with the motherboard I have selected. (I have Win8 consumer preview and I'm testing it out currently)
Your choices for the system are good though I am not a fan of the PSU you want. I'm a Corsair PSU person myself.
The system in a whole though should do great for you are wanting to use it for.