Become.com, a product information search engine, just launched.
With my first few searches (e.g. "6.1 sound card"), I was underwhelmed, but your mileage may vary.
It's certainly a good idea though. Despite attempts from Amazon.com, ePinions, Consumer Reports, and others, the Web has no authoritative, objective, comprehensive source of product information. Whoever builds that would be providing a useful and valuable service.
Chris Sherman has a detailed review.