Adobe's latest release is definitely worth the upgrade.
One of the most touted features in CS5 is its Content-Aware Fill function, which looks like magic and sometimes actually is. Sort of like the Healing Brush or the Patch Tool on steroids. It can actually create a pattern of pixels to replace whatever you're trying to cover up and remove. You can make a selection, go to Edit>Fill, and choose Use: Content-Aware, or set the Spot Healing Brush to make its decisions using the Content-Aware algorithm. Along with the Fill too, this allows you to replace huge areas with a fabricated patter-quick and dirty and often amazingly effective.
If youjust want to see how an image would look without a subject, or plan to mostly cover up the area with something else, Content-Aware Fill may be all you need. It works best with natural patterns and is great on skies. At the very least, it makes a good starting point that you can clean up with the Healing Brush.
But it's within the Healing Brush that Content Aware really shines. Spot-cleaning scanned slides and negatives and getting rid of blemishes on skin, works wonderfully. And, even better, it removes spots or lines that bisect differently colored edges. Whereas the Healing Brush often produced a smudgy mess, when set to Content-Aware, the edge is magically preserved. If you do a lot of spotting, this tool alone may be worth the upgrade.
BETTER BRIDGE AND RAW
To quickly locate pictures outside of Photoshop, first we had the lightweight File Browser, which grew into the heavyweight Bridge. Now in CS5 we have Mini Bridge browser, which lets you find photos without leaving Photoshop.
In Adobe Camera Raw, noise controls are much improved. You can add grain-useful when compositing a low-ISO images into a high-ISO one. Post crop vignette from Lightroom is also now in Camera Raw converter.
CS5 has more for photographers to be excited about than the last upgrade and you can check it out as a 30-day free trial.
Minimum System Requirements:
Mac: Multicore Intel processor, OS 10.5.7 or 10.6.3
Windows: Intel Pentium 3 or AMD Athlon 64 processor.