Typing keywords into the URL entry field in Firefox will take you to the top hit of a Google search -- the same thing you'd see if you clicked the "I'm feeling lucky" link on Google's search page. I discovered this by accident, and didn't think much of it at the time, and not certainly worthy of a posting, but I've found myself using it more and more. For example; finding info on a product, where I don't care which vendor site I go to, I just want the specs, a picture, and a ballpark price. So in the URL bar, I type akg 414 or mackie 1202.
For a quick reminder of details, try ortf or FM synthesis or John cage. Need the IRS' 1040ez form? Just type 1040ez into the URL bar. Also try things like art institute hours, babel fish, car talk london review of books, performance audio, and of course, apple store. Or try some software sites, like menumeter, amadeus ii, quickeys, or starquiz. Each of those take you to their site faster than doing a Google search and then clicking the top hit.
Not very fancy, but I love tricks that save me a click and four seconds.
[robg adds: I'm not positive this always runs an I'm Feeling Lucky search; a couple of examples I tried just led to Google's search results page. If I tried those same examples with the I'm Feeling Lucky button on Google, though, then I went directly to a given site. So I'm not quite sure what's going on...]
Mac OS X Hints
http://hints.macworld.com/article.php?story=2007050608292313