Zac Efron is gearing up to do the High School Musical feature film and the comedy 17 with Matthew Perry

Age
20

Network
Cool Dudes Who Sing and Dance

About me
What a year! Highlights: HSM2 rocked its debut (17 million viewers!), hit the big screen in Hairspray, got to show off my abs on the cover of Rolling Stone, and—thanks to our Hawaii vacation—I no longer have to pretend I'm not dating VH. Lowlight: All that gossip on the blogs—Yo, Perez! Cut me some slack! And I probably could have done without that YouTube montage of me dancing to "I Feel Pretty."

Zac's Friends
Vanessa Hudgens
Nikki Blonsky

Daniel Radcliffe is filming Harry Potter and the Half-Blood Prince

Age
18

Network
Seriously Rich Teens

About me
The fifth Potter film came out this summer, but I also shattered my boyish image by getting naked on the London stage. Yes, I'm still single, and as I told Details, "I think it would be very hard to go out with an actress, because they're mad.... They're all absolutely delightful. But completely barking."

Daniel's Friends
Rupert Grint
Emma Watson
Lord Voldy

Miley Cyrus is warming up backstage in yet another sold-out arena, then it's back to work on Hannah Montana

Age
15

Network
Hollywood Good Girls

About me
I can't believe how insane (in a good way!) this year has been: an amazing tour, a No. 1 album and a No. 1 cable TV show—full of cool guest stars like Brooke Shields! Plus, I watched my dad "dance" (ha!) on Dancing with the Stars.

What's next?
Hannah Montana: The Movie (yay!)

Miley's Friends
The Jonas Brothers
My crazy dad!

Rihanna is unwinding after wrapping up a hectic European tour

Age
19

Network
One-Name Pop Stars

About me
This year, I settled into my L.A. pad. My third CD just went platinum, and I was nominated for four Grammys. Plus I'm a CoverGirl, baby! Bring on those free lip glosses. I also amped up my style. Hope you like my new look. And, yes, I'm single. Sure, I've hung out with Shia and Josh, but you know how it is—we're just friends. One '07 bummer: Broke my toe, stubbed it on a chair, but I'm better now and not slowing down.

Rihanna's Friends
Shia LaBeouf
Josh Hartnett
Ne-Yo

Blake Lively is pondering whether to take a class at Columbia University next year

Age
20

Friends
Penn Badgley, Chace Crawford

Network
Beautiful People with Brains

About me
Don't get me confused with my Gossip Girl character. Sure, I love glamour, but I'm not such a fan of real-life gossip. (Note to paparazzi: Penn is a friend—we go way back. Enough with the Romance Watch already!)

Fave quote
I can't believe I actually told Cosmo Girl, "Stars really are like anyone else. At the end of the day, Brad Pitt poops—as handsome as he may be—and so does Angelina Jolie. I'm still baffled by how odd this job is."

Chris Brown is on tour with Bow Wow

Age
18

Friends
Rihanna, Bow Wow, Lil Wayne

Network
Future Kings of Pop

About me
I switched things up this year. The sound on my new album Exclusive has a bit of an older vibe. I also got way more into acting—I did The O.C. and hit the big screen (consider the yard stomped!). Oh, and did I mention I tore the roof off the VMAs and the Grammys? Watch out, JT.

Hayden Panettiere is still working on releasing her long-awaited CD and getting ready to promote Fireflies in the Garden, the movie she did with Julia Roberts

Age
18

Friends
Kristen Bell, Rumer Willis, Milo Ventimiglia

Network
Save a Dolphin, Save the World

About me
This year has been all over the place. The Heroes hoopla was amazing, of course, but my boyfriend and I broke up after a year together, and—believe it or not—I hear there's actually a Japanese arrest warrant with my name on it just because I tried to stop dolphins from being hunted. Give me a break. And that goes double for you, TMZ—ooh, you caught Milo and me walking arm and arm after the Emmys. Big deal. Friends do that, you know.

Michael Cera is filming Nick and Norah's Infinite Playlist, a movie about two teens who find romance at a punk concert

Age
19

Network
Awkward People

About me
Still waiting to get poked here, people. The whole point of being on Facebook is to get poked and if I don't get poked after the year I had—Superbad, anyone? Juno ring a bell?—when will I ever get poked? Web site plug: clarkandmichael.com. Check it.

Michael's Friends
Jonah Hill
Ellen Page