The Answer to that question is a resounding YES! CS5 is Aaa...Mazing! It is light years ahead of its predecessors (including CS4). This new version of Photoshop has packed a number of exciting new s and enhancements that help make photo editing quicker, easier, and an absolute delight! With CS5, image editing tasks that used to be painstaking and meticulous work can be accomplished with incredible ease. I'll touch on just a few of these new features that I consider the most useful:

Edge Detection for Selections  

Edge Detection saves you time by making selections incredibly easy. CS5 has made major enhancements on the Refine Edge Tool (first introduced in CS3) by incorporating the new Edge Detection feature into it. Edge Detection lets you effortlessly and accurately refine your selection after you've made an initial rough selection, say, with the Quick Selection Tool.

 Feature In Action: After a rough selection is made, click on Refine Edges on the toolbar. As in CS3 and CS4, this brings up the Refine Edge dialog box. CS5 has the new Edge Detection feature that helps you fine tune your selection. By using the new Touch Up Brush, you can "paint" over the edge of your selection and CS5 will almost magically remove any extraneous bits of selection and add to the selection areas you might have missed. If required, you can use the Decontaminate Colors (also a new feature) to remove any bits of background that might have spilled over into your selection.

How well it works: Edge Detection is one of the most, if not the most useful new feature in CS5. It works extremely well when there is a good contrast between the subject to be removed and the background. It makes selecting intricate regions such as the edges of hair or fur (which used to be a real pain!) almost effortless. With some practice, Edge Detection can save you a lot of work and time! It's no exaggeration to say that this feature alone is worth the upgrade!

Content-Aware Fill  

Content-Aware Fill fills in a deleted subject with the background. Traditionally, after a subject is removed from the foreground, you have to fill in the deleted area by painting it with cloned pixels. But with Content-Aware Fill, CS5 does this job for you.

Feature In Action: After an area to be deleted is selected, press the delete key. This will bring up a dialog box that gives you the type of fill to use: Content-Aware, Foreground, Background, etc. With Content-Aware selected, click on OK. Presto! CS5 automatically fills in the deleted area with the background for you.

How well it works: Content-Aware Fill doesn't always realistically fill in a deleted area. It all depends on the type of background the removed subject is in front of. The Content-Aware Fill works best with a landscape backgrounds like a beach or a meadow. It will probably NOT work very well in an urban area full of buildings, for example. With the "right" background, you can get away with deleting fairly large objects/subjects. For example, I was able to use Content-Aware Fill to successfully remove quite a bit of undesired foreground (mostly people and railings) in my Grand Canyon shots to produce convincing and natural-looking images.

Puppet Warp  

Puppet Warp lets you place control points on a subject and warp it or move parts of it as though it were Play-Doh (Fun stuff!).

Feature In Action: From the edit menu, select Edit/Puppet Warp. You can then click to add control points to manipulate your subject, such as a person (which would have to had been extracted from a picture). You can then bend, stretch, or warp your subject by moving any of the control points. Alternatively you can press the Alt key to make a point act as a "pivot" point, which would then act as a "joint" of sorts.

How well it works: Puppet Warp may seem like a toy at first sight since many of the demos use this feature for moving or manipulating the limbs of a person or animal - but Puppet Warp can be used for much more. When used on a person or an animal, if your intent is to create a realistic image, moderation in the transformation is key. However, if your intent is to create a goofy looking picture (much as you would with the Liquefy Tool), you can do some really wacky transformations in Puppet Warp. Puppet Warp has some serious applications too. It can be used to correct non-uniform distortions, which is a common problem in stitched panoramas. (For a demo, search for the "Puppet Warp Sneak Peek" video.) You can also use it to tweak the popular "smoke," "halo," or other layered effects that are commonly used on subjects in portrait photography. I personally find Puppet Warp an invaluable tool for this purpose.

Faux HDR  

Normal HDR requires 2 or more source images. CS5 lets you create a faux HDR with just one image.

Feature In Action: Go to Image/Adjustments/HDR Toning. CS5 immediately applies a default set of settings, which you can change to suit your preferences. There is a separate lightening/darkening setting for Shadows and Highlights. Other settings include color Vibrance and color Saturation, Exposure, Gamma, etc.

How well it works: The faux HDR is a great tool for salvaging photos where subjects are under-exposed because of backlighting. By using the tool to lighten the darker areas, you can make it seem as though you have a fill light on your subjects! However, lightening darker areas will inevitably introduce some noise. No matter, CS5 actually has a new noise reduction feature that does an amazing job. This HDR feature can really help you create surrealistic images.

Miscellaneous New Features & Enhancements  

CS5 has many niceties such as improved layer pasting called Paste In Place (pastes layer in the same coordinates as the source image), Lens Correction (corrects distortion, chromatic aberration, and vignetting), Mixer Brush and Bristle Tips (tools for blending colors and painting on your picture/canvas - not quite as complete a suite of tools a Corel Paint, but very impressive nonetheless!), Mini Adobe Bridge (a "mini" Bridge in-program), Adobe Repoussé (creates 3D objects from text layers, paths, and selections), and much more...

Additional Notes  

A lot of operations in CS5, such as Content-Aware Fill, is memory (RAM) intensive. Memory usage can easily run up in the GB range. On 32-bit systems, there is a limit on the amount of memory that Photoshop can use. Here's information about RAM usage taken from the adobe site:

Photoshop Version / Windows Version / Maximum amount of RAM that Photoshop can use
32-bit / 32-bit / 1.7 GB
32-bit / 64-bit / 3.2 GB
64-bit / 64-bit / as much RAM as you can fit into your computer

I use Windows XP (32-bit) and ran into a problem where the area I selected for Content-Aware Fill was too large. I got the message "Could not fill because there is not enough memory (RAM)." If you are using a 64-bit system, insufficient memory will not be a problem. CS5 is optimized for systems that use 64-bit addressing.

Conclusion    

In conclusion, the many new features and enhancements in CS5 will help you do more with your images to help you create great looking images in less time and with greater precision. There's no question in my mind that CS5 is well worth the upgrade.