John Lennon once famously commented that the Beatles in 1966 were "more popular than Jesus." In today's era of fleeting fame and what passes for real celebrity, few can claim a similar impact on the public consciousness. Oprah Winfrey is one.

Today, the talk-show host turned media juggernaut will air her last daily talk show after 25 years of family dysfunction, celebrity soul-baring, and the occasional free car. The end of Winfrey's chat-fest leaves a gaping hole in the daytime television schedule, and will bring to an end a seemingly unending streak of memorable TV moments. Who else but Oprah could have given us that red wagon full of fat (which equaled the 67 pounds she had lost) or the now-infamous Tom Cruise couch-jumping incident?

It's easy to make fun of Oprah's ubiquity and the adulation she garners from her target audience of middle-class women. After all, there's a fine line between the worthy exhortation to "Live your best life" and the hubris it takes to put your own picture on the cover of a magazine every month - for 11 years.

We may roll our eyes at Brand Oprah, who doesn't have children of her own but spawned a whole generation of media offspring, everyone from Rachael Ray to Dr. Oz to, some say, Barack Obama. But Winfrey's commitment to philanthropy, and her sincere efforts to improve the lives of young girls in Africa, balance the scales.

Oprah hasn't just spent the last quarter-century exploiting family sob stories and sharing celebrity gossip; she's also encouraged women to read, to seek better mental and physical health, and to empower themselves in ways that no female celebrity had the power to do before.

At age 57, Winfrey's life and self-made career are the embodiment of the American dream. Born into poverty and to a single mother in Mississippi, she began as a broadcast journalist but found her sweet spot in talk shows, a genre she single-handedly redefined.

That she managed to achieve such success in the entertainment industry without singing, dancing, or taking her clothes off is further testament to a unique intelligence, business acumen, and sense of self.

For all the attention, adulation, and airtime Oprah's final show has garnered, one might be forgiven for thinking Jesus himself was scheduled to make an appearance. Given the extreme secrecy surrounding the identity of the final guest, it seems we'll have to tune in at 4 p.m. to find out.