A short entry from the technological side.
Over time, I have had some experiences with partitioning, and there is one thing which I come across very often, but which has bitten me so many times I think it deserves dishonorable mention: The thought of recycling a /home folder among various distributions and various versions of the same distribution.
On the face of it, /home/yourname holds your files, and there is no place like ~ and all that. It does, however, merit a closer look - because /home holds all of - or at least most of - your settings.
What this means is that if you have an Ubuntu installation with a separate /home partition and then install, say, Fedora, those two will share the home folder, and if you are like me, you will use the same username to identify yourself. In other words, you will be using the same /home/yourname.
This means it will try to use your settings files when it comes up. All these files may be hidden, but they will influence the setup of the desktop you are logging into - any program which is also in you new distribution will take settings from the old one. This can be color schemes, to take a more harmless example (though I can not without pain imagine using Fedora, Mint or Opensuse with purple hues) - but you may come across a versioning conflict that will break your existing config files.
Though these things rarely happen, the potential for trouble is considerable.
And so, I have concluded that the best for me is to keep an individual storage partition. I put it on /mnt/storage, but that is of less consequence. In /mnt/storage, I have my library of texts, documentation and stuff I have written myself; I have my collection of audio: Audiobooks, podcasts and music; I have my collection of scripts; I have my collection of videos; I have my “Installers” folder with a collection of downloaded ISO images I need more than once, tarballs of certain drivers I need and the like. I have my collection of images, which is everything from screenshots over webcomics to my son being born. And there is my “Workshop” folder containing my half-baked scripts, my .po folders from the software projects I maintain translations for.
Once I install a new distribution, I create symlinks to my stored files in /home. And so, /home/morten/video to /mnt/storage/video will point to /mnt/storage/video, /home/morten/podcasts/ will point to /mnt/storage/audio/podcasts et cetera.
What this means is that my /home/morten will be unique for this distribution installation, but the files I need will be accessible regardless of what I have chosen to boot - the settings in the /home folders will not influence each other. If you have some more sensitive files, say, your script folder, you can make it read-only, so it is always available, but you can’t break it without concentrated effort; but that is a general consideration, not influenced by your partitioning.
There are, of course, several approaches to this issue, but I find this solution to be simple and functional.