The latest version of Ubuntu just came out; Ubuntu 13.04 - Raring Ringtail. Canonical, the company behind Ubuntu Linux, has done a good job setting up a set of defaults for a fresh install, but there are a few things you may want to add or change on your freshly installed OS.
1. Privacy Settings

You may want to adjust the privacy settings after you install Ubuntu. By default, Ubuntu provides online search results when you enter a search in the Dash. Each of these searches ends up running through Canonical's servers. It's a good idea to disable this function.