There's a pretty lengthy thread going on Lady knives here.
If she's interested in colorful knives then I'd take a look at Kershaw. They make some interesting knives.
I prefer fixed blade knives for defensive purposes but folders are better than nothing.
Something with a clip on it so that she has better access to it is nice as well. Even if she keeps it in her pocket she can use the clip so it doesn't get lost in her pocket.