Smashing Magazine consistently provides great articles and lists of information that will make a designers life easier. I check it out all the time and I’m always finding new techniques, fonts, and tutorials.  SmashingMagazine.com

The Web Design world is full of acronyms, abbreviations and catchy terms that can confuse many of us and our clients. Now you can usually just do a simple Google search and get the answer to your questions, but I keep finding myself being directed to The Motive Web Design Glossary.

I don’t know much about the company “Motive”, but I do believe that if a company is willing to share their expertise like they do, they must be a quality company.

-Thanks Motive

Pingdom.com

A great tool to test your website’s object loading and download times, it also breaks it all down into a Hierarchical manner. Objects including (images, CSS, JavaScript, RSS and frames/iframes).

EricDoolan.com site using Pingdom.com

Firefox Add-ons
https://addons.mozilla.org/en-US/firefox/addon/60
This has been one of my most useful tools I have when it comes to CSS and tweaking my websites. This add on basically has the ability to strip out the CSS, Disable the CSS, Edit the CSS, are you starting to see a theme here. It’s a great tool. Just download it and see for yourself.

• Ctrl + Shift + Y = View Style Information