Safari developer tools

The Safari developer tools are a nice alternative to firebug and
firefox. They are included with Safari, but you have to jump through
a few hoops to enable them:
On a MAC, with Safari shut down, type:
defaults write com.apple.Safari IncludeDebugMenu 1
(And make sure you are on your local system! My first attempt
failed. Then I noticed it was because I was logged in to a Solaris box!)
After starting Safari, a "develop" option will appear on the menu bar.
However, that is just the start. My favorite feature is the "right-
click" inspect feature. Similar to firebug. Though with some extra
features and notable shortcomings. (It bring it up in a separate
window, and makes it extremely clear what the element being inspected
is. However, it doesn't allow you to tweak the CSS.)
The error console is also nice - Safari always seems to be more
strict than Firefox, so it helps to more easily find what the real
problems are.
I've also found the network tab to be a little more accurate than the
NET tab in firebug.
Now if MS could just make a halfway decent debugging tool for IE...