Out put from my system
$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/sda1 184M 21M 154M 12% /boot
/dev/sda3 47G 37G 11G 79% /home/aaron/xp
/dev/sda5 12G 9.7G 1.4G 89% /
/dev/sda6 12G 149M 11G 2% /home/aaron/ort
/dev/sda7 193G 162G 22G 89% /home
separate /boot partition so that I set up grup once to boot to many os
after installing windows this has to be fixed google grup-update.
no that big only 190mb see that ony 12% is used.
I like to have my [xp,other os] partition as a primary partition the last one available is the third partition the fourth partition will be my extended partition which is the entire remaining disk space.
You need to take into account how much space you want available to the other OS. Windows can not currently read ext4 partitions that well. People are working on that.
I have a second root partition set up as ort(other root). So when I upgrade I do a clean install. I don't want to get burned by having an unbootable system. So I can always boot back to the previous system. I can also copy my /etc/* config files that I am rather attached to into the new system or use them as a reference if I am setting up a new system.
You should also have swap partition about the same size as your ram up to a max of about 4 Gigs. It would also depend on how you use your system. Even on some of my smaller machines with 2Gigs I never really start using my swap partition so about 2Gigs would be a lot.
Lastly I make home the rest of the remaining disk space. If you have a boot disk you can always boot up into it and resize you partitions later. You can't change the order of the partitions with out deleting them. So if you just shrink your home partition and add extra partitions after that. Make suer you have created and extend partition other wise you are limited to 4 partitions.