Have a think about how you want to arrange your data. While you can access windows partitions and files under Linux (and vise versa), it's better not to be constantly be mounting your windows C drive from another OS. Plus, if you're mid-update, or had to restart suddenly, windows will happily mark your drive as read-only.
I use 4 partitions for a dual boot. Sizes are based on a 1TB drive.
- Windows C (100GB or so, OS drive). Only mounted by Linux if I have a big problem.
- Windows D (NTFS formatted, my main storage partition. Mounted all the time by Linux. 700GB or so)
- Linux root (50GB or so, EX4 formatted)
- Linux storage (remaining space, EX4 formatted used for big programs, games, home folder)
This way, Windows OS is separate, main storage is accessible to both without tripping over permissions, linux root drive is separate from storage so reinstalling isn't so painful if something goes very wrong.