A sort of sleeper indie film, but Hope Davis in Next Stop Wonderland might fit into this category.

Perhaps Virginie Ledoyen in A Single Girl?

Nicole Kidman looked beyond gorgeous in TO DIE FOR.

Kim Cattrall in BIG TROUBLE IN LITTLE CHINA.

Virginia Madsen in ELECTRIC DREAMS.

Megan Fox in TRANSFORMERS.

Natalie Wood in THIS PROPERTY IS CONDEMNED.

Annette Benning in BUGSY.

JoBeth Williams in POLGERGEIST.

Claudia Wells and Lea Thompson in BACK TO THE FUTURE.

Sophia Loren in HOUSEBOAT.

Grace Kelly in REAR WINDOW.

Her wardrobe malfunction in Class was pretty spectacular too.

Do a Google images search for "Virginia Madsen Gotham." Many people had not seen it because it was an HBO original film.

The film that made me fall in love with Madsen was Creator.

Irene Jacob in The Double Life of Veronique was the first thing that came to mind.

But also:

Nastassja Kinksi, Cat People
Soledad Miranda, Eugenie de Sade

Rachel McAdams: Wedding Crashers

Kathleen Turner: Body Heat

Rachel McAdams also looked incredibly hot in Mean Girls, which turned out to be the same film where Lindsey Lohan had her beauty film.

I think Rachel McAdams is at her most gorgeous in Red Eye.

Actually never heard of that one, but yeah that's good too.

I always thought Scarlett Johansson looked her best in Match Point.

Another vote for Gene Tierney in Laura.

I love Barbara Stanwyck, but I don't think Double Indemnity is her 'beauty film'. I can't stand her hair in it. I would probably pick The Lady Eve for her.

I prefer Jennifer Connelly in "Inventing the Abbots"

Not from a movie, but this thread has gone way too long without some:

I'd actually say the Notebook for Rachel Mcadams. if you use slow motion (and turn the brightness up), she actually showed some full skin during the sex scene after the rain storm.)

Remember when Ashley Judd was usually just seen glistening and sweaty (in Heat, and A Time To Kill)?

Jamie Lee Curtis in Perfect

Melanie Griffith in Body Double

Sherilyn Fenn in Two Moon Junction

Madchen Amick in Dream Lover

Alice Krige in Ghost Story

Mia Kirshner in Exotica

Kim Basinger in 9 1/2 Weeks

Jacqueline Bisset in The Deep

Michelle Johnson in Blame it on Rio

Tuesday Weld in Lord Love a Duck

Rachel Ward in Sharkey's Machine

Kathleen Turner in Body Heat

Karina Lombard in Wide Sargasso Sea

Nastassja Kinski in Cat People

Ingrid Bergman in Notorious

A teenage Lee Remick twirls her baton enticingly in A Face in the Crowd.

Sandra Bernard - Hudson Hawk

Glad to find somebody else who has seen this.

Mama Guitar!

Kirstin Dunst - Crazy/Beautiful
Bridget Fonda - Jackie Brown
Phoebe Cates - Fast Times at Ridgemont High
Jean Seberg - Bonjour Tristesse, The Road to Corinth
Clara Bow - It
Angela Lansbury - The Picture of Dorian Gray
Liz Taylor - A Place in the Sun

In total agreement here.

Cameron Diaz - Shrek

For me it was Dead Men Don't Wear Plaid

and

Mondo Cane and Captain Zahn, Thanks for the passive recommendation. I forgot that I wanted to see this film (after watching Karina Lombard in L-Word 3 years ago). She's a pretty bad actress in it, but it's still a good movie.