Essential Tools for Web Design
HTML and CSS Validators
1. The W3C
The W3C offers validation service for both HTML and CSS. This website has everything a designer needs to develop and design functional websites.
2. WDG HTML Validator
Another HTML validator offered by the Web Design Group.
3. W3C CSS Validator
Direct link to the CSS validator at W3C.
Sitemap Tools
1. Site Map Pro Generate sitemaps for your website, for Google and Yahoo.
2. Audit MyPC
This website offers a number of tools including a sitemap generator.
Keyword Tools
1. Word Tracker
Word Tracker offers a free version, although scaled down, and a paid version.
2. Google's Keyword Tool
3. Overture's Keyword Tool
Forums
1. SitePoint Forum
Good forum for designers and developers. I often have found answers to my questions by just reading through questions and answers already on the forum.
2. SEO News Forum
Great forum for those who are optimizing websites for the search engines.
Web Page Analyzer
1. WebsiteOptimization.com
A web page analyzer tool. Website also offers other services for SEO.