One of the reasons I was still using Firefox on my mac for the past year was FireBug.
By coincidence I found the Web Inspector tool more or less at the same time Firefox started to crash constantly which just made my transition to Safari even easier.
To activate Web Inspector run the following command in a terminal:
defaults write com.apple.Safari WebKitDeveloperExtras -bool true
You will then have a new option called “Inspect Element” when you right click on a page, et voila, a much better looking Firebug and actually much more useful, but still having all those nice things such as request and response headers, download times, sizes and even helpful hints on how to improve your website speed!:
Now if I could just find a way to switch tabs with Apple + 1 , 2 , 3….apple, firebug, mac, safari