2. Phryne Fisher: the grown-up Nancy Drew in Kerry Greenwood's mystery series. She flies planes, drives a marvelous car, and takes down the bad guys with style and class. She is smart, independent, fights for the underdog, and is everything a strong character should be.
3. India Black: The Madame of Espionage by Carol K. Carr. Sassy and brave and keeping up with a secret agent. What more could you want.
7. Baroness "Jack" Troutbeck (from a series by Ruth Dudley Edwards): "Jack" is the no-nonsense, irrepressible and irreverant sleuthing partner to civil servant, Robert Amiss. Between the two of them, they manage to skewer all sorts of establishment positions from the ivory towers of education to the House of Lords.
8. Meg Murry (A Wrinkle in Time, etc.): a brave girl who travels through time to save her dad.
Didn't quite make it to Ten....and didn't want to steal from others whose lists I've already peeked at. But I did steal Falaise's title over at 2606 Books and counting...thanks, Falaise!