Nothing on the web is easy. I like wordpress and think it's easy to learn, but you can just as easily dedicate yourself to learning anything else. Pick the one that is you think will be the most beneficial to use, not by which is easier to learn because if you do that you aren't going to find that any of them are easy. They all require a lot of reading and learning.
This really depends and varies person to person. just i find joomla easier hen drupal and wordpress and joomla is more user friendly then drupal from client's point of view.. so better to learn and find out yourself.. industechnologies.co itechshop.org
What's you actual goal? You need to define your goal, then maybe we can help you decide which CMS to use - learning curve is not a good criteria for selecting a CMS.
Wordpress is probably the easiest to learn, in fact if you just want to create a simple website or blog then it is VERY easy to learn. But as previously mentioned, you need to decide exactly what it is you want from a CMS, and then start comparing from there.