If you're one whose search results lead you to a Wikipedia page nine times out of ten, you would do well to install the Googlepedia extension for Firefox.
This free, terrifically easy add-on pulls the Wikipedia article most closely associated with your search term into the right half of the search results page. Modest controls let you expand, shrink, or hide the article. Clicking a link within the article feeds the term back into Google's search engine, and therefore back into Googlepedia's cycle of serving articles.
Googlepedia will undoubtedly save you time if a quick search is all you need. If you're one to submit to Wikipedia's siren call of never-ending knowledge, download at your own risk.