Is it possible to do a complete system restore on Ubuntu?

I would also like to have a practicable recipe for that. If you have to store your 'home'-files, you could use dolphin or 'cp -axv <source> <destination>' in a terminal to store your files on an external usb-disk ...
A better way is to use a seperate /home-Partition, if you decide to format your disk again. There are also many configuration-files hidden in your /home- directory, you can let them appear with <Alt>. (dot) in dolphin.
But if your system is missconfigured, you shouldn't restore these files. I tried to boot with a live-cd (the same ubuntu-version), get with linking /dev, /proc, /sys in my old environment and working with 'chroot' to repair the system...
But i struggled deeper and deeper in new troubles; i still don't have a fresh system running.

@steve
http://askubuntu.com/questions/49869/how-to-roll-back-ubuntu-11-10-to-11-04
If you need more help, post again.
Before doing anything, do a backup of your /home directory. In theory, since 11.04 Ubuntu release are able to install system without touching /home folder, if you don't format. In theory...so do a backup.
To help future downgrading (or upgrading), you could make a dedicated partition for /home folder as advised emuede.

@emuede
It's better to use "cp -p" which preserves all properties of files. You can have a look with command "man cp".
Could you explain what you are doing, and what are your troubles.

I will perhaps also downgrade to 11.04, as Unity will probably not fit my needs to develop software. It's too much multimedia oriented and lot of software don't integrate well in new interface.