In case you've been under a complete self-imposed total media blackout - how do those work, by the way? - you no doubt know this week is a pretty important milestone in the lives of two of America's most important cultural figureheads. Maybe the two most important.

Oprah Winfrey is bringing her 25 years as a talk-show host to a close with a three-part finale taped last week at Chicago's United Center and featuring many of her best-known guests: Tom Cruise, Tom Hanks, Will and Jada Pinkett Smith, Stevie Wonder, Alicia Keys, Josh Groban, Madonna, Patti LaBelle, Maya Angelou, Dakota Fanning, Queen Latifah and Beyonce. The final episode airs in Houston at 4 p.m. Wednesday on Channel 11; rumors that the European principality of Liechtenstein will be Oprah's farewell "Favorite Things" giveaway were unconfirmed.

Bob Dylan, meanwhile, is celebrating his 70th birthday today by being Bob Dylan. This means that no one outside his immediate family, and maybe not even them, knows exactly what he's doing, except that he's not on the road right now. (His Never Ending Tour resumes June 16 in Cork, Ireland.)

As far as Rocks Off knows, Dylan and Oprah have never met in person. Oprah has mentioned Dylan on her show at least once, when Raquel Welch came on to dish about some of her past lovers. Apparently Bob is neither a "heat-seeking missile" or "high-octane energy set on idle."

Still, we thought it might be worthwhile to see how the two measure up in four crucial categories.

IMAGE

Oprah: Gabby galpal with kajillions of dollars and to-die-for speed-dial; life-coach coordinator nonpareil.

Dylan: Poet; prophet; jokerman; thief.

Edge: Dylan. Oprah's endorsement was so significant to Barack Obama's 2008 presidential campaign it now has its own Wikipedia page. At a White House performance in February 2010, Dylan was too cool to pose for a picture with the Commander In Chief.

Obama's response? ""That's how you want your Bob Dylan, right? You don't want him to to be all cheesin' and grinnin' with you," he told Rolling Stone. "You want him to be a little skeptical of the whole enterprise. So that was a real treat."

INFLUENCE

Oprah: Profound. Estimated weekly audience of more than 42 million viewers.

Bob Dylan: Limited to a small cadre of largely male singer-songwriters including Bruce Springsteen, Neil Young, The Beatles, Paul Simon, The Band, Eric Clapton, Tom Petty, Leonard Cohen, U2, Axl Rose, Jeff Tweedy, Ryan Adams, Conor Oberst, Jack White... and everyone who's ever bought one of their albums.

Edge: Too close to call.

FANS

Oprah: Can instantly send sales of any Oprah-appointed book, CD or household product through the roof. Often consider the talk-show host a family member.

Bob Dylan: Often employed as writers and/or editors at music-related publications. Have racked up a sizable bibliography comparing Dylan's lyrics to everything from Shakespeare to Scripture.

Edge: Oprah. Have you ever seen a Bob Dylan audience do this? (It gets good at about the 0:38 mark.) These days it's asking a lot for them to stay for the entire show.

DAVID LETTERMAN

Oprah: Letterman's frequent punchline/media foil, and occasional guest, since his ill-fated "Uma... Oprah" joke at the 1995 Academy Awards. Said he was "crushed" over not being invited to the finale taping.

Bob Dylan: Has appeared on Letterman's shows four times: A three-song set on Late Night With David Letterman in March 1984; as a special guest on Late Night's 10th anniversary show in January 1992; to play "Forever Young" after Letterman moved to CBS in November 1993; and in an October 1994 skit featuring Paul Shaffer jamming with Dylan's band at the Roseland Ballroom across the street from the Ed Sullivan Theater. Rehearsed, but did not perform on the air, Texas soul man Roy Head's 1965 smash "Treat Her Right" at his first Late Night taping.

Edge: Dylan. Even before Oprah's finale snub, Bob wins for "Treat Her Right" - even if Letterman turns out to be tomorrow's special guest host, which is entirely possible.

FINAL SCORE: Dylan 2, Oprah 1, 1 tie.