To make life easier for you why not make a simple research at The CMS Matrix - cmsmatrix.org - The Content Management Comparison Tool and compare the CMSes functionalites?

Before chosing the CMS for you site you must know what functionalites that you want to have and what for? Every CMS has its learning curve that you'll have to anticipate.

You can use Wordpress - which is simple to install with lots of free plugins and templates around. For more dynamic site you can use Joomla - quite a bit task to install especially if you're a newbie but lots of free templates and bots to add-on. I cannot comment on Drupal since I've limited experience in configuring this CMS.

It's really up to you - what functionalities/plugins that you want to have on your sites which really matters. Most plugins can be obtained free from the websphere.