My Everything Pak takes up 85gb on the shipped USB drive.
Maybe that will give you some indication, but I must warn you that you really do not want to "stuff" your C: drive full. That is dangerous. The drive your system lives on needs to always have about 10-15% free space on it at all times for running the Temp files that programs use, the disk swap/disk cache and for preventing wild fragmentations.
If you are that close, seriously consider a hard drive swapout to a larger C drive. Drives are getting kind of inexpensive today and many come with cloning softwares in the box that make not only the setup and formatting a breeze, they can clone your entire OS and all to the new drive in one mouseclick.
--Mac