I honestly have no idea how this has missed my attention previously.

Amazon's a9.com search engine takes google results (ie. it uses google) and adds more stuff:

• Amazon's search inside book
• Google images (presented with each search)
• IMDB (Internet Movie Database)
• Reference sites (dictionary etc.)

They even have their own version of the Google Toolbar at http://toolbar.a9.com/ and if you use Firefox you can add a9 to your search bar (go to http://mycroft.mozdev.org/download.html and search for a9).

Some of the Google keyworkds work, like site:, but not all of them.

I like it so far.

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On further investigation, the data gathering undertaken by a9 is pretty amazing. Every link you click, you may notice, redirects via a9.com and stores the click in your preferences.

You may prefer to use generic.a9.com which doesn't store any details in your Amazon profile.

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I also just re-discovered vivisimo.com and it's fantastic results clustering. I'm going to give it a shot as my main search engine for a few days. I'll let you know how I go. (As with a9, you can download a search plugin for Mozilla for it).