I've even gone through it removing things to keep it this small.
And I have all my software installed on D:\.
Part of the problem depends on what you are running I have things that just default to saving data in C:\Users with no option to move it elsewhere, i.e. game saves etc.
My Pagefile has been moved to another drive as well.
But having an extra 30 Gigabytes isn't going to cause any problems.
My C:\ drive is almost full at the end of a version update, before I remove the Windows.old files.
PS. I got curious as to where the space is being used.
My Users, Program Files and Program Files (x86) folders only total 10 Gigabytes.
But my Windows folder alone totals 29.1 Gigabytes.
I originally did a clean install of the first version and have been updating it since.
I guess it may be time for a new clean install for the next version.