Making search results accessible and relevant is always a challenge. Providing clear means to filter search results to get closer to the information the user is seeking is key - unless you are Google of course. Faceted classification and search results presentation has brought us a long way towards giving the users the sense of control over search results that can often be overwhelming.

Here are some examples of good faceted search interfaces:

The Classics
The sites that pioneered faceted search:

• UC Berkeley Flamenco
  Amazingly vast search interface to the UC Berkeley Architecture Visual Resources Library. Interestingly they have open sourced the interface and added other demos.
• Epicurious
  Pioneering but with all the clutter of ads on each page the clarity of presentation is lost in my opinion

Great Examples

• Home Depot
  Surprisingly Home Depot has one of the best example I have seen. Filters are clearly presented, number of results shown next to each options and the results are also neatly displayed for quick scanning
• NCSU Libraries
  No frills interface, that has 3 clear panels for filters and results list.

Okay Examples

• AbeBooks.com
  This online used books seller provides filters to narrow books by keywords, subject and other options, but the results list looks cluttered and does not give how the number of results users can expect for each filter
• Gifts.com
  Nice interface to filter gift ideas

• Getty Images
  Getty Images allows you to search their stock image library and filter your search results in the right column and rearrange and order your results. Perfect, if you know exactly what you're looking for.

And the plain weird examples

• IMDB: Husband and Wife Sleuths

Any other good examples?