Ask HN: Fair Use of Trademarks?

Are there any IP attorneys reading HN?

For a while I've had an idea to build a site where users can up/down vote consumer brands. In simplest terms, think of it as "Hot-or-Not" for Brands. However, it's been suggested that, while this might be fun and interesting, and it might be appropriately categorized as "fair use" of trademarks, that I'd most likely be inudated with cease and dessist request and lawsuits.

Can anyone shed any light ... would such use of trademarks belonging to others be fair use? On what basis then, are market research firms able to survey consumers on the brands they prefer? Do they get the permission of brands prior to their surveys? Is "Fair Use" real?