Ok, there are various searches you can find in the wild Google, Yahoo, Live or even something like Ms. Dewey.
Now there is one new thing – Tafiti. It is built around Live search, but adds some more interactivity like visual selection of content type (web pages, images or feeds) or tree results, where you can filter the results by relevancy.
Also, saving search result/link right there in the browser is very cool.
And one more thing: it requires Silverlight.