Firefox has a built-in search bar on the top right corner that makes web search quite easy, but you can make it even faster with Peers.
This Firefox extension provides real time results for any keywords you enter in that search field, so that you can directly open the webpage you're looking for without having to load Google (or whatever other search engine you're using) web results first. As soon as you type in the keywords, Peers will display a drop-down menu with the first results on the search engine, together with some search suggestions and other alternative search engines you may use.
The extension includes a quite complete configuration menu where you can select which search engines you want to use and how many search results you want to display, among other options. Apparently you can install additional search engines from the extension's settings as well, but this option didn’t work for me.
In all, Peers is a great extension to speed your web searches up, though it may need some polishing to fix some minor bugs.