Designing a Book Cover

Since I have a decent background in digital arts and my amazing friend Lydia is an awesome photographer, I decided to make my own book cover for my upcoming book "The Chronicles of Vallanie Sharp" (an excerpt of which is conveniently located under "excepts"). It's still in progress, but as I've come up with something satisfying, I thought I'd look back over the steps it took to get there. 

Here was a design I came up with a few months ago:

The eyes were annoying me. I kept changing their size, so you could see more or less of the face. I'm not happy with the way they are here. I was going to add something (likely a DNA strand) in the dark space at the bottom. I do like the way the text looks, and the black background. 

Here is a working sketch Lydia drew up:

I love the background picture. I love the purple. I actually really love this, except it doesn't fit the content of my book well enough. (Make's me think of a ghost/horror story. I'm going for more sci-fi/adventure, with perhaps a subtle creepy undertone). 

With something "dome like" in mind (since the story takes place in one), Lydia created with the following design:

While I loved the image, it again didn't fit the mood I was going for. 

So I tweaked it a bit and came up with the following:

Still, something was missing (the edge of the picture needed to be touched up, at the very least). 

And fixing that brought me to where I am now (ignore the difference in title... that's a whole different challenge I'm working on):

What do you think? Critiques are welcome, especially if they are accompanied with suggestions for improvement :)