The refine edge tool offers time saving in selecting specific parts of an image as well as enhancements to RAW processing including specific colour profiles for specific lens. Which lens are included, im not sure on but apparently the focus is on common Canon and Nikon lens for the time being.
HDR (High Dynamic Range) feature now has a "remove ghost" option that eliminates any object that moves inbetween shots. This i believe should be very useful for me as i've always struggled with this. How effectively it works is yet to be determined.
Overall it looks like there will be some features that make this a winner and better than CS4 which aside from technical bugs that were never solved, didn't really push the boundaries from the prevoious version CS3.
If anyone has CS5 (in particular CS5 photoshop) i'd love feedback as to your thoughts?