As you already know Content Management System is famous for providing webmasters with multiple convenient facilities for content manipulation. But there are different options this or that CMS may possess, so in order to make it clear for you here is the list of cool CMS facilities.

1. WordPress
Being a basic platform for everyday writing earlier Wordpress has become nowadays a CMS distinguished by full functioning. Though Wordpress main destination is still everyday writing there is a great number of plugins which can help you to create any web presence - from brochure sites and photo galleries to powerful ecommerce websites.
Wordpress is distinguished by the easy to use standardized backend with various functions and allow you to do all necessary things in any section easily. You can make use of WYSIWYG editor which provides all facilities you may need, e.g. pasting photos, videos, audio files, and allows to switch between HTML and Visual modes.
Wordpress basic platform is very simple and supports posts, pages and other standard options such sites provide. For more functionality you should use special plugins which exist in great variety.
Wordpress is easy to work with even for beginners, besides it maintains great documentation which covers every aspect from simple instructions to handling advanced facilities.
And also there is a lot of forums to find fixes for any bug you stumble upon.

2. Radiant
Built on Ruby on Rails Radiant CMS will come in handy if you need to create a basic site with a huge amount of pages. It has a logical simple backend with layouts, pages and snippets, where the functions work similarly in spite of the section you work in.
Radiant is considered to be somehow limited in functions, but you may extend them on your own if necessary. For example, If you need to add blog or gallery to the site you should make use of special extensions.
The documentation of Radiant is not massive but the CMS is considered to be extremely easy to use,so there should not arise any problems. Anyway you can always address to developer community and find there a vast documentation for developers.

3. SilverStripe
SilverStripe is known to be a fully-functioning CMS built in PHP on the Sapphire framework which gives more facilities for customization. The CMS is distinguished by the possibility for designers to customize the backend for every client, showing necessary fields they need to access. This makes SilverStripe easy to use even for those who have never worked with CMS before. Besides, it provides free support,IRC channel, forums and documentation for end-users and developers. With SilverStripe you will create any pages you like without difficulties.

4. Joomla!
Nowadays Joomla is known as one of the most popular open-source Content Management Systems running on PHP and MySQL. Its straightforward backend allow you to manage articles, media, menus and other content within sections. Joomla WYSIWYG editor provides you with a great amount of formatting tools plus you can always find  extensions to make your Joomla even more powerful. There is a lot of plugins which can improve its functionality,just choose the one that possesses specific features you are interested in.

5. TYPOlight
Using PHP5 and Ajax TYPOLight CMS possesses functionality for blogs, static sites, newsletters and calendar sections. The backend offers a great amount of facilities, your content is displayed in modules which you can style with CSS.
TYPOLight has easy to work with WYSIWYG editor for fast and easy publishing of your content and also provides a lot of customization options, developer tool like form generator and built-in CSS generator. You can find all necessary documentation for end-users and developers, as well as forums where you can also find support. In case you or your clients require some advanced help you can receive paid support services.