Why should you try XFCE ?
Ubuntu 11.04 uses ‘Unity’ desktop by default but if you are running ubuntu on a older hardware/computer or got tired with the slow performance of other desktops then Xfce is the right desktop for you. Since, Ubuntu has very modular structure you can install as many desktop as you want; it means you don’t need to go for Xbuntu distribution – The Xfce version of Ubuntu, if you are already using Ubuntu or any other flavor of Ubuntu. Xfce 4.8 is the latest stable version available, released in Jan 2011. You can install it either from command line or Synaptic Package Manager, and it works not only for ubuntu but also for other Linux distros such as Linux Mint, Fedora etc.Installing XFCE Desktop on Ubuntu 11.04
step1 : Open terminal and type (You may need to authenticate yourself by login password):sudo apt-get update
sudo apt-get install xfce4
step2 : Wait until the installation is complete. Next, logout from the current session and select Xfce session in login prompt.
step3 : That’s all.. Enjoy XFCE.. if you want to use other desktop then just select it at the login prompt.