Ubuntu 8.10 Release Candidate now available
If you're using Ubuntu 8.04, you can also upgrade automatically. You can find instructions in the release notes.
Intrepid Ibex features a number of updates since Ubuntu 8.04, although not enough to make the entire operating system unrecognizable. Users should notice a new version of the GNOME desktop environment with support for tabs in the file manager, and a bunch of bug fixes. There are also new optional desktop themes.
If you're using Ubuntu Studio to edit audio and video, it's recommended that you not upgrade to Ubuntu 8.10 yet, since it uses Linux kernel 2.6.27 which can cause some latency problems.