When working on a site, there are a plethora of tools available to help you out. I have a few favorites that I use all the time, and would be crippled without.

• TopStyle  [ http://svanas.dynip.com/topstyle/ ]
  TopStyle contains powerful tools for building standards-compliant web sites. I definitely under-utilize this tool, since I only use it for the CSS editing. For this task however, I could not ask for a better tool. Full definitions, and live preview make this invaluable.

• [Firefox] FireBug  [ http://getfirebug.com/ ]
  Firebug integrates with Firefox to put a wealth of web development tools at your fingertips while you browse. You can edit, debug, and monitor CSS, HTML, and JavaScript live in any web page. What more can I say about this tool? If you don't have it, you are not working efficiently. Extremely helpful in debugging site state problems, it will also help you work out almost any design issue in a snap!

• [Firefox] Yahoo! YSlow  [ http://developer.yahoo.com/yslow/ ]
  YSlow analyzes web pages and suggests ways to improve their performance based on a set of rules for high performance web pages. Having recently discovered this tool, I find the advice given very helpful for optimizing the sites I work on as I deploy them to live servers.

• [Chrome] lipsum.com extension  [ https://chrome.google.com/extensions/detail/jkkggolejkaoanbjnmkakgjcdcnpfkgi ]
  Fetch a given number of paragraphs or words of 'Lorem Ipsum' text and put it in a text-field so you can copy it. 'Nuff said.

• [Chrome] Speed Tracer  [ https://chrome.google.com/extensions/detail/ognampngfcbddbfemdapefohjiobgbdl ]
  Speed Tracer is a tool to help you identify and fix performance problems in your web applications. Every bloody stat you could possibly want to know about your site speed.

• [Chrome] Webpage Screenshot  [ https://chrome.google.com/extensions/detail/ckibcdccnfeookdmbahgiakhnjcddpki ]
  Fast&Simple extension to capture the whole webpage Eventually everyone needs to email a page screenshot to someone.

• [Chrome] Window Resizer  [ https://chrome.google.com/extensions/detail/kkelicaakdanhinjdeammmilcgefonfh ]
  What is there to say? You have to resize eventually, to make sure a design is good.