In addition to the sexy stuff, Adobe does a great job of adding refinements to each release of Photoshop. I just found this article by Jason Anderson, Five Best Kept Secrets of Photoshop CS5, and he lists some nice touches that you might not know of. My favorite of the bunch?
Sharing Your Monitor -- In CS5, the feature has been added where you can share your monitor with others so you can show people exactly what you are looking at. I can totally see this as a feasible solution for clients that are remote to your location, and travel costs need to be kept down. Even training seminars could be conducted this way...imagine sitting at your computer at work (or home) and watching an instructor teaching you live from their own desktop!
Be sure to check out the other four best kept secrets by Jason.
More About Photoshop CS5