For my work, I partition my hard disk like this:
/boot 500 MB primary partition Ext4
/swap 32 GB primary partition Ext4
/ 120 GB primary partition Ext4
/home the rest of the hard disk logical partition Ext4
I mainly store files. /home gets the most of the space.
There should be enough space for the programs. There should also be enough space for the boot loader of GRUB in /boot.
Partitioning the hard disk is good for backing up, e.g. by Redo Backup and Recovery.