By David Kiley
Reviving even a storied brand isn't easy once consumers have a negative perception of it. Just ask Ford or Gap, which lost 19% and 15% of their brand value, respectively, in this year's BusinessWeek/Interbrand annual ranking of the 100 Best Global Brands. Even such perennial winners as Coca-Cola (No. 1) can have trouble boosting their brand. The beverage giant claimed the top spot for the seventh year in a row mostly because it is big and everywhere, but it failed to further burnish its reputation because its move into healthier drinks and snacks has yet to resonate.