Ed Stevenson at Really Strategies Blog - One of the best search experiences:

"On kayak.com, you are offered a set of dials and levers for adjusting the query, such as eliminating airlines, changing departure time frames, or looking for the shortest trip. You want to leave between 10 and 12, just move the dial and the page is updated with results that match. You want to find the shortest trip. Move the lever.

Does your content, or its metadata, lend itself to this type of search? Is there a way to present options for your customers to refine search results in a more appealing way?"