JQuery a framework that makes JavaScript development much easier and has become the solution of choice for web designers and developers.
In this post , you'll find 20 Best and Must Have jQuery Plugins and Tools that serious webmasters and developers should know and take advantage of to enrich their site (both in easy navigation and graphical prospect).
Aptana Studio is the industry leading web development environment that combines powerful authoring tools for HTML, CSS, and JavaScript, along with thousands of additional plugins created by the community.

The powerful editor for JavaScript, XUL/XBL and Yahoo! Widget development. The JavaScript editor provides features like code completion, syntax highlighting and content outline that helps developers productively create efficient JavaScript code.

DataTables is a plug-in for the jQuery Javascript library. It is a highly flexible tool, based upon the foable-so
undations of progressive enhancement, which will add advanced interaction controls to any HTML table.

This is a powerful jQuery component to build easily a multilevel tree menu or a contextual menu (right click) in an intuitive way!

It allows a user to more easily enter fixed width input where you would like them to enter the data in a certain format (dates,phone numbers, etc) and has been tested on Internet Explorer 6/7, Firefox 1.5/2/3, Safari, Opera, and Chrome.

A jQuery plugin that checks a user’s input as they fill out a form.

Komodo Edit is a fast, smart, free and open-source code editor. A new Invoke Tool dialog makes finding and using dozens of useful tools in the Toolbox easy.

Ajax Fancy Captcha is a jQuery plugin that helps you protect your web pages from bots and spammers.

TableSorter is a jQuery plugin for turning a standard HTML table with THEAD and TBODY tags into a sortable table without page refreshes. tablesorter can successfully parse and sort many types of data including linked data in a cell.

Google Charts GUI uses the Google Charts API to create its charts, so as you can imagine, they look great.

Lightweight but rich data grid with resizable columns and a scrolling data to match the headers, plus an ability to connect to an xml based data source using Ajax to load the content.

The jQuery UI Datepicker is a highly configurable plugin that adds datepicker functionality to your pages. You can customize the date format and language, restrict the selectable date ranges and add in buttons and other navigation options easily.

markItUp! is a JavaScript plugin built on the jQuery library. It allows you to turn any textarea into a markup editor. Html, Textile, Wiki Syntax, Markdown, BBcode or even your own Markup system can be easily implemented.

The Multiple File Upload Plugin (jQuery.MultiFile) is a non-obstrusive plugin for the jQuery Javascript library that helps users easily select multiple files for upload quickly and easily whilst also providing some basic validation functionality to help developers idenfity simple errors, without having to submit the form (ie.: upload files).

Ad Gallery takes a simple unordered list of images and then converts them into a, much more presentable, gallery.

slideViewerPro is a fully customizable jQuery image gallery engine wich allows to create outstanding sliding image galleries for your projects and/or interactive galleries within blog posts.

Easy Slider 1.5 is jQuery plugin that offers many features such as auto slide, continuous sliding, "go to first" and "go to last" button, hiding controls, vertical sliding, multiple sliders on one page, and many more.

HTMLBox can convert any textarea into a visual editor. It is very feature complete and packs in just about any formatting option you could ever need!

Visualize is jQuery plugin that turns regular HTML tables of data into charts.

Tooltips Done Right can set up tooltips with any HTML you like, including images and tables.

You are most welcome to suggest any additions to this list. You can use the comments box below to make any suggestions.