By Michelle Tauber
February 02, 2004 12:00 PM

It’s tough to imagine Oprah Winfrey almost bald, but the talk show queen came close. “About five years ago, Oprah said, ‘You know, when I turn 50, I’m gonna shave my head,’ ” says Gayle King, her best friend of almost 30 years. “She saw [Bill Cosby’s wife] Camille, who looks so chic with that short haircut.” With Winfrey’s milestone birthday fast approaching on Jan. 29, King recently asked her pal when she’d be going under the razor. Her reply? “I changed my mind.”

If there’s one overriding theme from the first 50 years of Winfrey’s life, it’s this: When Oprah makes up her mind—or, for that matter, changes it—anything’s possible. These days her mind is set on greeting her new decade with passion. “I feel like I can’t wait to get to be 50,” Winfrey tells PEOPLE. “I want to make everybody jealous and wish they were 50—or 49 and going to be!” Notes Maria Shriver, a pal since the two met as young journalists 25 years ago: “She’s in an extraordinary place. The feeling I get is never one of, ‘Oh my God, I’m turning 50.’ It’s, ‘How grateful, how happy, how lucky am I?’ ”

Of course, Winfrey’s got plenty to celebrate: Her talk show, now in its 18th season, is earning some of its strongest ratings to date; her body is buff enough to dazzle in a Gianfranco Ferré dress at last month’s People’s Choice Awards; her 17-year relationship with motivational author Stedman Graham, 52, is going strong; and, oh yeah, last year her net worth of more than $1 billion made her the first African-American woman to earn a spot on Forbes magazine’s annual tally of billionaires. But topping her list of birthday wishes come true is a sense of fulfillment that has accompanied the half-century mark, thanks in part to a life-altering trip to South Africa in 2002. “At 50, you know a lot more than you did when you were 25,” says Winfrey, “so you can use all that stuff you didn’t know to propel yourself forward. I feel like [turning 50] is everything you were meant to be in your life.”

With that in mind, Winfrey tossed around several ideas for celebrating her big day. In addition to the shaved-head notion, she contemplated climbing Mount Kilimanjaro: “That plan died a very quick death,” says King, 49, with a laugh. After Winfrey declared that she’d be happy simply relaxing at home, her friends settled on the idea of planning a three-day weekend celebration following her big day. “She always throws such wonderful parties, so we wanted to do something that would just blow her away,” says King.

The blowout bash marks a rare lack of control for the media mogul, who does not tend to turn over the reins of power easily. Between her business empire—which includes the flagship Oprah Winfrey Show, O magazine and investment in the women’s cable network Oxygen—and her expanding charity work in South Africa, where she is building a school for girls, Winfrey is hardly slowing down with age. “She works very, very hard,” says Graham. “She’s up at 5:30. She’s out the door at 6. Then she starts her day. After work she comes home and has to get ready for the next day.”

Her daily routine also includes a 45-minute cardio workout, plus 30 minutes of weight training several days a week. “Maybe for the first time, she’s doing it for all the right reasons,” says her longtime personal trainer Bob Greene. After a lifetime of dieting, Winfrey is now following a sensible eating plan—no refined sugars or starches, light dinner and absolutely no food at least three hours prior to bedtime—but with room to enjoy herself. At the 23,000-sq.-ft. home Winfrey and Graham share with dogs Solomon and Sophie in Montecito, Calif., Winfrey loves to whip up her favorite dishes. “Her corn fritter pancakes are the best in the world,” says Graham. “And the fish! Nobody cooks better fish than she does.”

Fritters on the griddle, buckets of cash in the bank—despite the heavy workload, life is definitely sweet for Winfrey these days. And yet, as her personal life at 50 remains much the same as it has in every prior decade—no husband, no kids—the persistent questions remain: Will she and Graham ever wed? Will Winfrey ever become a mom? “I don’t think that’s for me,” she told Larry King in December. Noting her relief work in South Africa, where the children call her Mother Oprah, she added, “I feel that I have a calling.” Just not a calling to start her own brood. “It’s taken me about 10 years to realize that she doesn’t have the desire [for kids],” says Gayle King. “She knew she could not do this job and be the kind of mother she would want to be.”

Marriage too is hardly on the radar. “I’ve seen the radar, and I don’t see that blip on the screen,” says King. As Winfrey recently told TV Guide, “Stedman and I have a great relationship that allows me to be me in the fullest sense, with no expectations of wifedom and all that would mean.”

If Winfrey seems wary of “wifedom,” her famously rocky childhood offered scant evidence of its virtues. Born in tiny Kosciusko, Miss., to housekeeper Vernita Lee, Oprah spent her early years shuttled between her grandparents’ farm in Mississippi, her mother in Milwaukee and her father, Vernon Winfrey, in Nashville. “She has thanked me,” says Vernon, 71, a barber shop owner. “She said, ‘Daddy, if you had not been a strict disciplinarian, I would possibly be somewhere in public housing with a bunch of children.’ ”

Having come a long way from Kosciusko, Winfrey has made the most of her vast fortune, snapping up a $20 million property on Maui in 2002 in addition to her estimated $50 million Montecito spread, which she bought in ’01. “She’s embarking on a new journey there,” says Shriver, “and I think that’s been one that’s made her very happy.”

As the journey continues, Winfrey, who recently renewed her Oprah contract through 2008, is already looking ahead. “She’s proud of her career but not nearly thinking that this is the upper limits for what she can do,” says long-time friend Diane Hudson. The birthday girl herself agrees. “I am going to rock it out,” says Winfrey of her benchmark year. “I feel like it is just the beginning of a whole new level for me.”

Michelle Tauber. Lauren Comander, Lorna Grisby and Kelly Williams in Chicago, Sean Daly, William Keck and Cynthia Wang in Los Angeles and Jeannie McCabe on Maui