Wow, I love it! Quite different from the wallpapers usually submitted. The monochrome was an excellent choice and the mist looks fine to me. The light spot behind the girl was a great idea - it draws your eye directly to her.
The only thing that I would change is the text. The font looks too elegant for the atmosphere you created. And I think it could be placed somewhere else (perhaps in the mist?) as it takes away the focus from the girl. Still a great job though and I hope to see more walls like this from you. ;)