A freshly installed Ubuntu is like a small baby, it will learn only if it is taught, likewise Ubuntu initially lacks video and audio codecs and the style, word processors, photo applications and many useful tools. It is good when you tweak and install the softwares you need and upgrade the user interface. I am going to show you the possible software and features you will be needing :

Note:- The commands used should be typed in the Terminal. (To open terminal go to Applications–>Accessories–> Terminal or press Ctrl+Alt+T). And you will also need Internet connection.

1. Update your system

sudo apt-get update && sudo apt-get full-upgrade

Now all your programs will run on the last version.

2. Anti-Virus

Windows equivalent : AVG AntiVirus, NAV, TrendMicro, F-Prot, Kaspersky

Ubuntu equivalent : ClamAV, Avast

ClamAV

sudo apt-get install clamav clamtk

Access it through System Tools → Virus Scanner

Avast

wget http://files.avast.com/files/linux/a...3.0-2_i386.deb && sudo dpkg -i avast4workstation_1.3.0-2_i386.deb

Access it through Accessories → avast! Antivirus

3. Essential tools for Compiling from Sources

sudo apt-get install build-essential checkinstall cdbs devscripts dh-make fakeroot libxml-parser-perl check avahi-daemon

4. Java runtime environment

Java is a very important thing to install, now that many programs like Azureus need it to run. So type:

sudo apt-get install sun-java6-jre sun-java6-plugin equivs