JCE is another popular extension of Joomla. JCE is a free content editor that provides the web designers with a set of WYSIWYG editing tools. The JCE is free, extendable and can also be customized according to the requirement of the designer. It makes writing articles for Joomla web design and related things a tad bit easier.
Xmap is based on the hugely popular Joomap extension. It allows you to create a map of the site you are designing based on the structure of your menus. It also fixes several bugs that had been reported by many Joomap users in the past.
JoomlaXplorer is the File and FTP manager. It allows you to edit, copy, delete, rename and archive files directly on the server. Using the JoomlaXplorer is easy and that is probably the reason why it is so popular with web developer these days.