Welcome to the Ubuntu Forums
I suggest that you try several of the Ubuntu 'flavours' or 'family' desktop environments alongside standard Ubuntu with Unity. A combination of your preferences and how it performs with you hardware will decide what you will use in the end.
Lubuntu - with ultra-light desktop environment LXDE, no current LTS.
Xubuntu - with light desktop environment XFCE, LTS until April 2015.
Ubuntu - with standard desktop environment Unity, LTS until April 2017
Kubuntu - with fancy desktop environment KDE, LTS, unsure to which date
Ubuntu server - with text mode interface, LTS until April 2017
There are also several community re-spins and remixes, that you might find and like.
And there are several versions (time-wise ordered). The current long time support version is 12.04 LTS, now at point release 12.04.3, but 12.04.4 will soon be released. The currently newest version is 13.10. If you have very new hardware or if you want or need some very new software, try 13.10, otherwise 12.04 LTS is probably the best choice, because it is well debugged and polished by now (it was released in April 2012). The next version, 14.04 LTS, will also get a long time support, probably for all four main flavours.
If you have a fast internet connection, download several desktop iso files and test them 'live', Try [KLX]Ubuntu without installing. Else you can install the desktop environments to an installed version of standard Ubuntu and select desktop environment at the log in screen.
It should be possible to remove the desktops that you don't like, but it might cause problems, so it is probably better to test and then make a fresh installation of the system you prefer.
sudo apt-get install lubuntu-desktop
sudo apt-get install xubuntu-desktop
sudo apt-get install kubuntu-desktop