I have CS2 and it IS worth the upgrade

Improvements with tools, filters and the new Vanishing point cloning make things a lot easier. The improved noise reduction gives better results than neat Image with some images. The Smart sharpen tool also gives very good results, and motion and lens blur repair has been made very easy with this tool (when configured for the photo being repaired).
IMO CS2 is much better than CS for restoration work. As I don't do much glamour retouching, I can't say if the improvements would help, but I am VERY impressed with it
