The latest version is U.S. $199.00, and upgrades are available for any existing Aperture users for $99.00.
Apple says Aperture 3 has “more than 200 new features“, including Faces and Places, which has been brought over from iPhoto ’09. Aperture 3 also adds nondestructive brushes, which allows you to paint effects onto certain parts of an image. If you wanted to add polarization to the sky of a photo, you could choose that effect, adjust the size of a brush, and paint the effect on the sky.
Furthermore, Aperture 3 offers a new full-screen view, which will allow the users to work on projects, thumbnails, and even the Browser in full-screen view.