According to the DBI, an independent index typically used by brand marketers to determine a celebrity's ability to influence consumer purchase intent, Obama's scores in "appeal" are 15 points higher than those of Clinton and 12 points higher than McCain.

The Illinois Senator also scored 12 points better in the DBI's "trust" attribute than Clinton and McCain.

"In terms of appeal and trust, in the minds of U.S. consumers, comparing Obama to Clinton is like comparing Tom Hanks to Martha Stewart," said Jeff Chown, president of Davie Brown Talent, a Dallas-based agency that works with major brands to identify and sign celebrities for endorsement deals. "There's a big drop-off between how they're perceived when it comes to likeability and trustworthiness."

Of the DBI's eight key attributes, Clinton tops Obama in just one: Awareness. But just barely. According to the DBI, Clinton is known by more than 99 percent of U.S. consumers, while just less than 99 percent of consumers know Obama.

"That one's essentially a draw," said Chown.

But Obama outscores Clinton -- as well as Republican frontrunner McCain -- in the DBI's influence, endorsement, aspiration, trendsetter, and breakthrough categories.

"Barack's influence scores on the DBI are on par with celebrities such as Jay Leno, Jack Nicholson, and Vince Vaughn," said Chown. "At the same time, in terms of influence, Hillary is in the same neighborhood as Willie Nelson, Candice Bergen, and Billy Joel."

Of the more than 1600 celebrities in the DBI database, Obama currently ranks third overall. Clinton is eighth overall, while Republicans McCain and Mike Huckabee come in at 20 and 74, respectively.

  Oprah Winfrey, a strong Obama supporter, currently ranks first in the DBI