Whitney Elizabeth Houston (Brown) 1963-2012

 Genre appearances included...

Rodgers & Hammerstein's Cinderella (Fairy Godmother / performer: "Prologue", "Impossible", "It's Possible", "Finale Ultimo", "There's Music in You")
The Preacher's Wife (Julia Biggs)
The BodyGuard (Rachel Marron / performer: "Queen of the Night")

 Note: The BodyGuard is not really genre, but it's use of footage from the classic 1926 film Metropolis as well as the Maria-Robotrix-influenced costume prominently featured in the video for "Queen of the Night" and the film itself make it worthy, IMHO, of inclusion.

Check out...
Whitney's Official WebSite
A cool FanSite

Other actresses to play Fairy Godmother in Rodgers & Hammerstein's Cinderella include Celeste Holm [1965] and Edie Adams [1957]

Other actresses to play Julia Biggs include...
Actually, in the previous version of this film, The Bishop's Wife [1947], the character was named Julia Brougham and played by Loretta Young.

Maya Khabira Rudolph

You don't think "science fiction / fantasy" when you think of multi-talented Saturday Night Live alum Maya Rudolph.
Why not?
Currently appearing in BridesMaids, she hasn't done much genre, but what she's done recently has been either top-billed or featured player!
But perhaps her biggest Fantastic Femme credit was her uncanny ability to impersonate other Fantastic Femmes including Halle Berry, Lucy Liu, Beyonce, Vanessa Hudgens, and Whitney Houston during her tenure on SNL!
Trivia:
One of Maya's closest friends is Gwyneth Paltrow, whom she's known since grade school!
Maya is the daughter of legendary soul singer Minnie Riperton. Her greatest hit, "Lovin' You", was conceived and written by Minnie as a lullaby for baby Maya!

Genre appearances include...
Shrek Forever After / Shrek the Third (Rapunzel)
The Simpsons "Homer of Seville"
Idiocracy (Rita)
Devil's Child (Holly)
Gattica (Delivery Nurse)

Check out...
her bio on Saturday Night Live's Official Site

Other actresses to play Rapunzel include...
Mandy Moore in Tangled
Tereza Srbova in InkHeart
Emma Rose Lima in Enchanted
Kelly Sheridan in Barbie as Rapunzel
Tress MacNeille in The Simpsons "Treehouse of Horror XI"
Louise Robey in Play Nice
Pamela Winslow in Into the Woods
Stephanie Walski in Pee Wee's PlayHouse
Shelley Duvall in Shelley Duvall's Faerie Tale Theatre "Rapunzel"
Carol Lynley in Shirley Temple's StoryBook "Rapunzel"