I would have to say Scarlett Johansson. Not to popular yet though. Have a look: http://simpsonjessica.blogspot.com/ (gallery at the top, dont mind the name of the blog) ?
there may be some models that are hotter, but if we're gonna do very famous people, i'll go with Jessica Alba. http://www.wallpaperbase.com/wallpapers/celebs/jessicaalba/jessica_alba_3.jpg