FireBug, GreaseMonkey, AdBlock, DNTMe.
NoAds Advanced, Ghostery and WOT (for Opera)
firefox and chrome
adblock for sure Awesome Screenshot color picker else…
Every one is using AD-BLOCKER then what is the use of placing ads on website. totally waste. It’s so sad
Bookolio Chrome addon
Everyone has most of the mentioned addons. I love Wappalyzer. It analyzes page head tag and header and tell what cms or web modules are used in the page.