Starting with Ubuntu Linux 7.10
Its advisable to get a proper internet connection as this will save you from lot of hassles.
Once ubuntu is installed,work on the following points
1. gstreamer plugins for support of mp3/mpeg and other multimedia files
2. icedtea-java7-plugin package to have support for Java in browsers like firefox and mozilla
3. vlc player to play all kind of files
4. video drivers if you are using the VESA driver card, I got
myself the correct drivers from ATI, I am uisng the ATI Radeon card.
5. Get Automatix installed, this can help you with missing plugins.
6. Learn using apt or synaptic(graphical client to apt), this will surely help in installing the above packages
7. Visit http://www.futuredesktop.com/ for other tips on Ubuntu