I am running Windows 8 Pro 64bit on my 32GB SSD. On the first day, I had about 3GB empty after installing Windows onto it. Now, a few weeks later, it's down to less than 100MB. My "personal" folders such as Documents, Pictures and Videos, etc are all empty. My downloads folder is empty, and I am downloading things to my 2TB HDD. I don't have any programs or games installed to the SSD, and my recycle bin is empty too. Nothing is stored directly on the desktop. I run the disk cleanup, and it only clears about 4MB of temporary files.
Windows updates , every day useage with adding files and transfering data back and forth. 32 gb is just way too small to put a 64 bit Operating system on it and even if you were able to get the 3 gb of space back to what was there at the start you have filled the SSD too much and you should not fill it past 80% of capacity.
A 32 bit Operating System would have taken up a lot less space.
I wouldn't even put a 64 bit OS on a 64gb SSD.