What is the best free open source CMS (content management system) solution?
I want to convert a website to use a Content Management System for updating a large number of content pages for a website.  The current website is mostly ASP.NET, but I am considering converting to PHP if it means I will have better integration with the "CMS of choice" in the market.  I have heard of Joomla! and other CMS' but I would like some answers to which ones are considered better.  Features that I need to support are custom sidebar and tab menus (with expandable javascript drop downs for example).  Can anyone tell me of a good solution?
What is the best free open source CMS (content management system) solution?
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I want to convert a website to use a Content Management System for updating a large number of content pages for a website.  The current website is mostly ASP.NET, but I am considering converting to PHP if it means I will have better integration with the "CMS of choice" in the market.  I have heard of Joomla! and other CMS' but I would like some answers to which ones are considered better.  Features that I need to support are custom sidebar and tab menus (with expandable javascript drop downs for example).  Can anyone tell me of a good solution?