I quite like Tafiti . Search results can be presented as a newspaper page which works surprsingly well, and results can be dragged over to the right and labelled. The filter within option is also easy to get to, and the blogs/pictures/documents/news/web...
I use and like IE7's Instant Search box. The IE7 search architecture relies on OpenSearch Description which allows multiple search providers can be installed, which are then easily switched between - so you can check the same terms quickly in multiple...