Photoshop CS4 is here, and it's laden with new functionality that will increase your productivity and make common tasks easier. There are a few entirely new functions thrown in, as well as a refined interface, GPU acceleration and even support for online screen sharing via Adobe's Connect Now technology.
CS4 is an evolutionary upgrade from CS3 rather than a revolution, but the sum of all the improvements and enhancements makes it a worthwhile purchase. Top of the must-have list, surprisingly, is the new GPU acceleration. While it might not sound like something that will make any difference to the program, it entirely alters the way you interact with Photoshop. Zooming and panning are now a joy, rendering is much faster, and you can even rotate your view of the canvas seamlessly without having to wait for Photoshop to re-draw the image.