A magical teenager with an eye for Chanel. A 20-something trend-setting actress and budding fashion designer. A 35-year-old tomboy-by-day, fashion-icon-by- night. A 41-year-old hottie who makes pregnancy look chic. A 58-year-old Oscar-winner happy to flaunt her figure. And an actress in her 60s who puts women a third her age to shame.

To celebrate our annual pick of the year's best dresses, we selected celebrities who represented six age groups and who gave great style in 2007.

No matter their ages, they could teach us all a fashion lesson or two.

20s: Sienna Miller

Trend-setting girls everywhere look to this British actress for styling tips. She was a red-carpet staple in 2007, promoting her role as another style icon, Edie Sedgwick, in Factory Girl. She also launched a fashion line, Twenty8Twelve, with her sister this fall. Miller gets points for keeping things simple (she's most often seen in white, black or red) but adding just the right amount of edginess to make her outfits standouts.

From left:

Jan. 15: In a metallic-embellished white Marchesa gown at the Golden Globes in Beverly Hills.

Sept. 5: In Twenty8Twelve at the line's Bergdorf Goodman launch in New York.

March 13: In a sequined Balenciaga minidress at the premiere of Factory Girl in London.

30s: Cameron Diaz

She might be a jeans-and-T-shirt kind of gal by day, but when it's time to dress up, Diaz loves to show off her gorgeous gams. Even when she goes for a glamorous gown, she still adds her own fashion stamp. She's not afraid to take chances and have fun with fashion.

From left:

June 8: In a white Marchesa tuxedo minidress at a premiere of Shrek The Third in Berlin.

May 6: In pink Chanel at another Shrek the Third premiere, this time in Los Angeles.

May 7: In fuchsia Dior by John Galliano and turquoise jewelry at the Metropolitan Museum of Art Costume Institute Benefit Gala in New York.

60s: Helen Mirren

She may have won the Oscar this year for The Queen, but Mirren also established herself as fashion royalty in 2007, showing that 62 can still be sophisticated and sexy. Mirren sticks with neutral shades of white, gold, silver and black, but she isn't afraid of a little shine, lace, beading or a plunging neckline to show off her fabulous curves.

50s: Meryl Streep

Her wardrobe was divine in The Devil Wears Prada, and Meryl Streep continued to work that fashion-editor edge on the red carpet this year. She doesn't opt for fads or trends but instead wears clothes that look both chic and comfortable at the same time. And, like all good fashion icons, she adds her own flair to each ensemble.

From left:

Jan. 15: In a gold Carolina Herrera gown at the Golden Globes in Beverly Hills.

Feb. 25: In Prada, of course, and her own jewelry at the Academy Awards in Hollywood.

40s: Halle Berry

Halle Berry is proof that being pregnant does not mean your style has to suffer. The Oscar winner has been spotted wearing designer clothes, despite her growing bump.

From left:

Oct. 24: In blue Versace at another Lost in the Fire premiere, in London.

Oct. 26: In Dolce & Gabbana at a premiere for Things We Lost in the Fire in Rome.

On the cover

From left: Emma Watson at a Chanel fashion show in London on Dec. 6; Sienna Miller at a movie premiere in London on Oct. 3; Cameron Diaz at a photo call in Rome on June 15; Halle Berry at a movie premiere in Hollywood on Oct. 15; Meryl Streep at the Golden Globes in Beverly Hills on Jan. 15; and Helen Miren at the SAG Awards in Los Angeles on Jan. 28.