Remember when Firefox 3 first came out, and one of the cool new features was realtime in-address-bar search?
So I have to say, I didn't like it at first; it seemed annoying, because I couldn't predict what it was going to do. But now after several months of using it I love it. It has become the fastest way for me to get to something, even when I know exactly where it is and could find it with a few clicks. For example, Aperio's slide gallery, which just requires that I type aperio.com/gallery. That is not much typing, but now I just type "ga" and poof, the Aperio slide gallery is at the top of the search list. Wonderful.