There are 2 different CDs available from Ubuntu: the Desktop CD and the Server Install CD.
It sounds like you probably down-loaded and installed the Server Install CD.
However, the suggestion to install "ubuntu-desktop" sounds like a good one. (If you prefer KDE, install "kubuntu-desktop" instead.)
The only disadvantage to installing one of the "-desktop" packages, instead of fetching and installing the Desktop CD, is that you may have a bit of server software that you don't want, taking up space.