Linux only: The Addictive Tips blog writes up a quick tip that can help you trim down some of the fat from your Ubuntu installation—do you really need the Bluetooth service running?
By default, Ubuntu starts a number of services that really aren't necessary for everybody—but they are started to make the operating system work for the maximum amount of people. It's not a bad thing, but since you are running Linux you are obligated to tweak and customise it to fit your own needs—most people probably don't need the Braille display management or Bluetooth services, for instance.
To tweak the services for yourself, head over to System -> Administration -> Services, click the Unlock button, and then remove the check marks from the services you want to disable. Hit the link for the full screenshot tour.
How To Disable Unwanted Services In Ubuntu Linux [Addictive Tips]