I've recently switched from Opera to Firefox. One of Opera's features that I'd really like to have in FF is the address bar search. For instance in Opera I can type "g whatever" in the adress bar to search google. I've found extensions that do this but they're not customizable at all.

In Opera I had the possibility to add whatever search I wanted. I had a bunch of stuff in there like "a something" for the Arch Linux wiki and "imdb movietitle" for imdb.com.

Is there a Firefox extension that will give me this functionality?

Please don't tell me to use the search box on the right. I don't like having to click a separate box and click even more just to change search engines. I just want to type some quick commands.