Which Actress Should Be Cast for the “Fifty Shades of Grey” Movie? [GALLERY]

I've already run down the suggested actors to play Christian Grey for the big screen adaptation of the "Fifty Shades of Grey" book trilogy.  But who will play the female lead, Anastasia Steele?  E.L. James (the author) describes Ana's look as "A pale, brown haired girl with blue eyes too big for her face."

Would it make sense to cast an unknown actress, or someone well established in Hollywood?

A recent Twitter poll voted Alexis Bledel and Emmy Rossum as top contenders.

Here are some of the suggested actresses who may be in line to play Ana.  Who would you like to see cast as the female counterpart to "50 Shades?"