What are some useful web development kits that save the most time?

IDEs :

- NetBeans

- Eclipse

- Dream Weaver

- Aptana Studio

Version Control Systems:

- GIT

- SVN

code diff (files and folders compare tools)

- diffuse

- windiff

i agree with my colleagues previous and i add

.NET 

DevExpress

Telerik

Dreamweaver

Code ignitor

firebug plugin

1. Macromedia Dreamweaver

2. Netbeans IDE

Front-end

HTML5 Boilerplate

jQuery UI

AngularJS

Backbone.js

Ember.js

Twitter Bootstrap

CoffeeScript

Cappuccino

Codekit

ComponentJS

PHP

Laravel

CodeIgniter

Drupal

WordPress

Zend Framework

Joomla

Javascript:

Node.js

ExpressFramewrok

Socket.io

Derby

Python

Flask

Django

Ruby

Ruby on Rails Sinatra

Java

Hibernate ORM

Play Framework

For Front End, used predefined frameworks like Twitter Bootstrap, Foundation, Telerik and so on.

For Development, use CMS's like Wordpress, Joomla, Drupal, Concrete, Php-fusion, Radiant and so on.

For Data Binding and Manipulation, use JS Frameworks like Angular, Backbone, KnockOut, Microjs and so on.

it really depends on project description personally if i am starting custom project i use given below tools to run project faster.

1> bootstrap for front-end

2> Codeignitor or laravel framework for big development back-end if simple project i use object oriented php

for project like blogs and simple websites i will going to use wordpress to save time with customizable theme