I want to have dual OS of Win8 & Ubuntu 12.10. Provided that Ubuntu can access ntfs partition of Windows but same can't be said about Windows this leads to a question mark on the significance of having /home partition while installing Ubuntu.
As far as I know /swap & / are the two partitions directly used by Ubuntu to store programs, installation & stuff while the documents/media resides in /home. Now because Ubuntu releases are more frequent than Windows & updates needs backup & relate stuff, so I came to decision to not to use /home at all, rather keep all my documents/media in ntfs, which would be untouched while upgrading Ubuntu as Win updates are once in a decade!

Is my thinking correct? If yes, what would be the minimum space I should allot to /home plus how much I should allot to / one must know that I plan to use heavy applications like Maple, Matlab & Sagemath on Ubuntu.