Well as you have been told back up your entire home directory to a usb
key, CD, DVD or external harddrive or other source.

Now my suggestion is when you install 8.10, partition your drive so that
you have 3 partitions.
1 for swap, 1 for your / (root), 1 for your /home.
With this setup the next time you upgrade using a CD you can reformat
the root partition and not your /home partition.
Then you point the installer to use /home but not format, this way when
your system comes up after reboot your settings and files are retained.
All you have to do is reinstall anything that is not installed by
default within the Ubuntu CD.
Everything that you do as a regular user in Linux is saved to your home
directory so as long as that partition is not (re)formatted you won't
lose that information.


My suggestion is at least 1GB for swap, 40GB for /, and the rest for /home