Komodo Edit is a great editor if you're looking for something powerful, yet simple.
Other features include Vi emulation, Emacs keybindings, Code Folding, and Code Snippets. XPI extension support provides the same capability as Firefox, with all standard Mozilla APIs based on XUL, XBL, and XPCOM, plus own for Python and JavaScript. XPI extensions allow you to create your own plug-ins.
Background syntax checking and syntax coloring catch errors immediately, while autocomplete and calltips guide you as you write. Komodo Edit from ActiveState is a free, open-source, multi-platform, multi-language editor (PHP, Python, Ruby, Perl and Tcl, JavaScript, CSS, HTML and template languages like RHTML, Template-Toolkit, HTML-Smarty, and Django).
