Most useful programs for SEO developers

Like all web developers specialists and SEO, I use different tools to carry out the work. I use a combination of desktop and Web applications, some purchased and some free. Of course, need to start free download Mozilla Firefox, and then take some of the useful extensions of the programme. There is expansion, which are needed for use. Following are my favorite some extensions for web professionals
HTML Validator (http://users.skynet.be/mgueury/mozilla/) - checks the Web pages HTML W3C standards with a simple green checks in the corner of the page if the page confirms red check if it doesn "t, and a yellow exclamation sign, if there are warnings. It also includes checking the source code, which allows you to see errors in the code.
FireFTP (https://addons.mozilla.org/firefox/684 /) - free, secure, cross-platform FTP client, which provides an easy and convenient access to FTP-servers. This makes it possible not to use a separate program FTP.
Professor X (https://addons.mozilla.org/firefox/2823 /) - provides an opportunity to view information in the header, without viewing the source code. The "hill" down and Professor X displays the contents page of the head element, including Meta, Script style and content.
NikkelWHOIS (https://addons.mozilla.org/firefox/2646 /) provides an opportunity to quickly obtain information WHOIS for any page by clicking on the upper right corner of the browser.
IE Tab (http://ietab.mozdev.org/) - patients in exchange between Internet Explorer and Firefox when testing of the web page you are creating? In IE Tab you can browse the Internet Explorer to Firefox Tab!
FireBug (https://addons.mozilla.org/firefox/1843 /) - advanced debugger console, which allows to observe JavaScript, CSS, HTML and Ajax.
Codetech (https://addons.mozilla.org/firefox/1002 /) - editor of web pages, which as close as possible to Dreamweaver. Remarkable expansion for everyone who makes a web design, but wants to save several hundred dollars to Dreamweaver.
Server Switcher (https://addons.mozilla.org/firefox/2409 /) - makes it easy to switch between objects and switch servers, simply clicking the switch server.
SEO for Firefox (http://tools.seobook.com/firefox/seo-for-firefox.html) - you can conduct market research data directly to Google and Yahoo!. Search results include Google PR, Alexa rank, WHOIS, and much more. He also adds a few useful links at the top of search pages, including Google Trends, Google traffic, and Overture
Yet Another Window Resizer (https://addons.mozilla.org/firefox/2498 /) - allows you to instantly resize the browser window in accordance with a resolution of the screen.
AdSense Preview (https://addons.mozilla.org/firefox/2132 /) - view Google AdSense ads that will appear on this page. This is very useful if you're using AdSense on the page and do not want to go through the hassle of signing up for by ads and putting up just to see what type of ads will appear.
Screen grab (https://addons.mozilla.org/firefox/1146 /) - makes screenshot web page and saves it as an image file. This will save much time compared to standard.
Spy Server (https://addons.mozilla.org/firefox/2036 /) - indicates what type of HTTP-server (Apache, IIS, etc.) used by site visitors.