You may have heard talk about the "JDI" improvements in Photoshop CS5. In this "Just do it" initiative where the Photoshop team took a long wish list they had compiled and addressed as many of these things as possible, for one week. As a result there were over 3 dozen small but important additions to Photoshop CS5.
If you're a NAPP member you can watch a video I did that shows 10 of these changes, but here's a quick run-down on a few.
Make Default button in Layer styles
Change the opacity of multiply ayers at once
Straighten button in the Ruler tool options
Heads-up Color PIcker (quick access to the Color Picker anywhere in the window)
Improved Workspace menu
Scrubby Zoom (Zooming in and out by dragging left and right)
Change brush size and softness by dragging
There are a ton more, and it's one of the cool parts of Photoshop CS5: small changes and additions that you'll use every day (based on suggestions from people like you)