Mozilla Labs launched the next step in the Prospector experiment "Instant Preview". Now, as you scroll through possible results that get highlighted in the Awesome Bar suggestions will automatically start loading, so by the time you confirm that the first result is the one you want, the page may be ready for you to use.
Mozilla Labs points out that you can also use it for 'temporal' information, such as weather and stocks news, or a Web comic. Type the first two letters of your favorite comic into the Awesome Bar, and the comic automatically loads. Read it, then simply press Esc and the Web page you were looking at before instantly re-appears.
Instant Preview is best used with Speak Words, and the easiest way to get both is by installing Lab Kit on a Firefox 4 Beta. But you can also install the two individually without too much trouble as all of these add-ons do not require restarting the browser.