60 would be enough space as you can always place software and games on the spinner to open. This is what I did and even after a year I still had 18% free after upgrades and updates and I'm told that you can use up much more of the available drive space and it operates with ease unlike a spinner. But old mind sets are tough to change so I put it in my girlfriends system and purchased (2) 128gb's for my lappy and desktop and this is really the sweet spot as all the music, photos, data and for me games go on the spinner.
Lastly the time is now to consider your case and power supply and if chosen wisely they will outlast your build and future changes many times over. With this future savings in mind please consider a 1000+watt PSU. You will have so much voltage headroom that it will run cooler, quieter, more efficiently and as the caps age and lose a little power each year you will still be safe for upgrades and add on. Smart money spent now will save big for many mobo's and CPU's.