Content Management

I'm going to start up a site again, so I've been looking around for some sort of content management scripts.. I know of a few.

What I need is to know what else there is.. whats easily customizable.. has the most "plugins" and such..

 

Depending on your knowledge of coding on the website, the most popular content management system would be Wordpress.

I personally advice against all content management (open source / pre-made), systems, but if that's what you need Wordpress works.
Another alternative to Wordpress is Joomla. You can find a good article with a long list of CMS's here: http://en.wikipedia.org/wiki/List_of_content_management_systems#PHP

Hope this helped.