Here are some great tools to use!
CoffeeCup - A great resource of Web Building Tools. CoffeeCup has a large selection of tools that help the everyday Web Designer builder websites. Their software ranges from full HTML Code Editors to WYSIWYG Editors, a very slick Web Form Build, Image Editing software, Sitemapper, Fonts, Themes, Books and much more!
Theme Forest - A place to get some cool themes for HTML, CSS, Wordpress, Joomla and more!
Graphic River - A place to get Stock Graphic files.
Active Den - A place to get Flash and Flex files.
Video Hive - A place to get Royalty Free video Files.
3D Ocean - A place to get 3D Models and Accessories.
Free Icons - 99 Icon Sets to use in Commercial Design Projects.
GTMetrix Site Speed Test - GTMetrix a really nice tool that helps you find out what your page load speed is, and how you can fix it. It provides compressed images for you, and very helpful articles that tell you how to go about making the changes.
Yahoo! Site Speed - An article that will help you learn some of the standards of site speed.
W3C - World Wide Web Consortium. The people who make HTML and CSS!
Westciv Tools - XRAY and MRI are useful tools as well as the gradients and shadow maker on this site! Check it out.
Insicdesigns - Great articles that explains how to implement different scripts, CSS and so on into your site.
Browser Shots - A site that will take a screen shot of your site and show you what it looks like in different browsers... A must have for any Web Designer.
Browser Testing - A site that will take a screen shot of your site and show you what it looks like in different browsers... A must have for any Web Designer. This site is not free...
Responsinator - A place to view your site and many different size formats. Such as Iphone, Ipad and Andriod. Beware this site does show flash, where as most devices will not.
Site Compression - If your site is slow loading, you may want to try this site. It will help you learn how to setup your .htaccess file.
IE Bug Fixes - Name says it all. This will aid in finding and fixing almost all bugs in IE.
Google Video Blog - This is Google's Webmaster Blog. Very helpful information. This will take time to watch and learn. I suggest you do watch it...
Webmasters Tools - Another Web Designer must. The tools given by Google are a wonderful asset to any Web Designer.
Light Box 2 - A useful photo gallery add on.
SEO - An article that has some helpful tips on SEO.
Ajax Load - A site that has loading images that are free to use.
Gradient Editor - This site allows you to make a CSS3 gradient and see what it will look like before you add it to your site.