60gb for os is more than enough.
Thats my 60gb ssd drive which contains the os and a few downloads. It has never ever been full or near full. However, as rudie suggested, a 1600mhz ram is recommended. Other than that, you shouldn't go for the 960. Amd rx 480 is coming up in a week and it is better, cheaper and newer than 960.
edit: not sure if the 500gb hdd is going to be enough. It is a lot but I'm not sure if it can handle all that incest anime download.