One of the things I like about Firefox is its extensibility; there's a huge selection of add-ons available to extend the browser. One that I use quite a lot is the Web Developer add-on, even though I'm not really a Web developer. (There are any number of Web development extensions available for Firefox; probably the most extensive is Firebug, which I also have installed.)
Safari apparently doesn't have a feature like that...but it actually does; it's just disabled by default, and needs a bit of help to work via the keyboard. In Safari's preferences, go to the Advanced tab, and check the box to show the Develop menu in the menu bar. Once checked, you'll (instantly) see the Develop menu appear in the menu bar; once you're sure it's there, close Safari's preferences.
Click on the Develop menu, and you'll see six separate "disable" menu options for various web site features. You can certainly leave things as they are, and just visit the menu whenever you want...but that means a lot of reaching for the mouse. To make things simpler, you can create keyboard shortcuts for the disablers you use most often. In my case, that's Disable Images and Disable Styles.
Open the Keyboard & Mouse System Preferences panel, then click on the Keyboard Shortcuts tab. Click the plus sign at the bottom of the window to add a new shortcut.
In the drop-down sheet that appears, set the Application to Safari, the Menu Title to Disable Images, and then enter a suitable shortcut in the Keyboard Shortcut box (I used Shift-Control-I). Click the plus sign again, and repeat the process for each additional menu item you'd like to access via the keyboard.
If you're running OS X 10.5, your changes will take effect immediately in Safari (as seen in the image above); if you're running 10.4, you'll need to quit and relaunch Safari to see the changes. Now, to disable any of a page's elements, just press your shortcut key, and then press Command-R to reload the page.
This story, "Disable Web Site Elements via Keyboard in Safari" was originally published by Macworld.