But, I would buy at least 120gb and preferably more.
There are many files that want to be on the "C" drive.
Your drive will fill up quickly.
As a ssd fills to near capacity, it will slow down and lose endurance.
I will have another 1tb hdd and a 500 GB external hdd, i just want to have my OS installed on the ssd. My friend has a 120 GB ssd, and he installed windows 8.1 and mozzila firefox on it and it only took 40 gb of space.
A 60gb ssd will format to a smaller useable space. Perhaps 55gb. Once you get to 90% full my computer will show your capacity in red. That will not be very far off.
Also, a 120gb ssd will perform better. It pays to do it right up front.