Just like the title says. I Have already backed up my home folder. Is there anything in /etc/ or /usr/share I should back up?
Thanks
Not particularly. If there are any applications present on your system of which you want to back-up the configuration files, you should.
Upgrades seldomly result in data loss, as no manipulation to the partitions is done.
You should backup everything. This is just a general principal, and has nothing in particular to do with the 11.10 -> 12.04 upgrade. I didn't have any issues when I upgraded my machine. I recommend backing up everything just to be "safe rather than sorry".