I am willing to download Ubuntu for VMware..I'm much confused among Ubuntu Server and Ubuntu desktop,which one should i go for? and what is the differnce between them?
There's one version of the Ubuntu Server, and it does not include any GUI, so if you're comfortable with the Linux CLI (Command Line Interface), it will run faster, and gove you the opportunity to add many services during installation.
You can also use official versions of Ubuntu, described at Wikipedia's Ubuntu page with a GUI: Edubuntu, Kubuntu, Xubuntu, Lubuntu, Ubuntu (Unity) and Ubuntu GNOME. These and other versions are linked from the Ubuntu official releases page. Although these will not prompt you for services during installation, you can add them later through apt-get, the Synaptic Package Manager or the Ubuntu Software Center.