Star Couples: Should They Marry?

With a baby on the way, could a ring not be far behind? Insiders have said it's likely once Pitt adopts Jolie's kids Maddox, 4, and Zahara, 1 – but for now the Mr. amp Mrs. Smith stars are content as committed do-gooders. "This is a perfect situation," says a source close to Pitt.

Diaz, 33, and Timberlake, 24, have proved their staying power, despite nearly a decade's age difference. In nearly three years together, they've deflected breakup, engagement and baby rumors – and hit the surf, the dance floor and the slopes. "We are all pleasure," Timberlake says.

PEOPLE's Sexiest Man Alive, who began dating his Sahara costar Cruz in 2004, may have met his match in the Spanish siren: She's just as game for blackjack and camping as she is for the red carpet. But as for marriage? McConaughey says "maybe" he's met the right woman. But, "has it been the right time? Obviously not."

The on- and off-screen couple have been through plenty of drama on The O.C., but in real life they keep their relationship quiet, shopping in L.A. and walking their pit-bull terrier, Penny Lane. But there's no hiding their attraction: Brody and Bilson shared a 2004 Teen Choice Award for best TV chemistry.

"I don't say if he's my boyfriend or not," Beyoncé once said – but she doesn't really need to. A couple since 2002, Jay-Z, 36, and Beyoncé, 24, say it all with their body language – whether vacationing in Italy, cuddling courtside or even dueting. Still, those engagement rumors get the brush-off, with Beyonce's insistence: "I'm 24 years old!"

After three years of dating, Bloom, 29, and Bosworth, 23, broke up for seven months early last year, but then went right back to where they left off: cuddling, kissing and spending time with the actor's dogs, Sidi and Essa. Bosworth, says Bloom, is "an amazing woman."

Despite their age difference (she's 18; he's 26), the pop princess and the Good Charlotte rocker say their relationship of almost two years is the real thing. "We think about the future," Madden, who surprised Duff by visiting her on tour in Canada, told Teen People recently.

Wedding bells could be ringing for reunited sweethearts Sheridan, 42, and Bolton, 52, whose first go-round was more than a decade ago. "I am very committed," Michael Bolton told New York's Daily News recently.

"The fact that we can do meaningful things together is the perfect balance of any relationship," says Barrymore, 30, of her boyfriend of almost four years, Strokes drummer Moretti, 25. She's also his biggest supporter: The actress can often be found hitting the floor with fans at his shows.

Things seem to be getting serious for the fellow Aussies, both 38: Since November, Kidman has sported a diamond on her left ring finger, and the couple spent Thanksgiving and Christmas together at Urban's Nashville home.