The clipboard management is something really important for me at the time of using an Operative System. Diodon is an excellent clipboard manager that is integrated with Ubuntu and its Unity interface.
To install it we just need to use the PPA available from their Launchpad site (since the next Ubuntu version, 13.04 Raring Ringtail, Diodon will be available from the official repositories), we can make it on a console:
sudo add-apt-repository ppa:diodon-team/stable sudo apt-get update sudo apt-get install diodon
Once installed we can run it from the Dash looking for their name, diodon.
A little icon will show up with a clip shape on the Indicators bar (or a blowfish if you aren’t using the default Ubuntu icons). When you press this little icon you will get a list with the last words or files copied or marked, and option to clean this list, go to the preferences or to close Diodon.
On the preferences windows we can define keyboard shortcuts, the number of entries to keep, enable some addon and more.