I haven't used most of these, but will look into a number of them.
For monitoring, I use montastic, because it's free if I set it up with the client's email address, not mine. (I think you get 3 for free and I've already used those under my email address.)
Also, I made a userscript named "gist-to-dabblet" that adds a Dabblet link button to any associated gist. It's useful for switching back and forth between the two sites quickly ;)
Most of these are pretty self explanatory
Online Tools
http://jsfiddle.net/ *I strongly recommend
http://sqlfiddle.com/
http://dabblet.com/ *I strongly recommend
http://mothereffinganimatedgif.com/
http://mothereffinghsl.com/
http://mothereffingtextshadow.com/
http://border-radius.com/
http://noisepng.com/
http://html5please.com/
Downloads
http://www.sublimetext.com/2 *I strongly recommend
http://aptana.com/
http://netbeans.org/
Toolbox
http://html5boilerplate.com/ *I strongly recommend
Chrome Extensions
https://chrome.google.com/webstore/detail/ninejjcohidippngpapiilnmkgllmakh
https://chrome.google.com/webstore/detail/hmdcmlfkchdmnmnmheododdhjedfccka
https://chrome.google.com/webstore/detail/bfbameneiokkgbdmiekhjnmfkcnldhhm
Monitoring
http://www.pingdom.com/
The list could go on forever so I've only included the ones I can't live without
What ones do you use?
I haven't used most of these, but will look into a number of them.
For monitoring, I use montastic, because it's free if I set it up with the client's email address, not mine. (I think you get 3 for free and I've already used those under my email address.)
http://gskinner.com/RegExr/
http://filezilla-project.org/
http://www.chiark.greenend.org.uk/~sgtatham/putty/
Here are a few other online tools that are useful:
http://www.colorzilla.com/gradient-editor/
http://www.westciv.com/tools/radialgradients/index.html
http://csswarp.eleqtriq.com/
http://apps.eky.hk/css-triangle-generator/
Design Bookmarklet
Also, I made a userscript named "gist-to-dabblet" that adds a Dabblet link button to any associated gist. It's useful for switching back and forth between the two sites quickly ;)