Strengths: Nice new features in areas like RAW and B&W conversion
Summary: I use Photoshop almost exclusively for developing photos, so found the new & improved features of CS3 well worth the upgrade.
The improved RAW processing alone I've found to be worth it all by itself, and a couple new features like black and white conversions were long overdue. Bridge is certainly improved, too, as is startup time.
Overall, however, this is very very similar to CS2, and if one doesn't regularly shoot RAW format, for example, there may be little or no difference noticed from CS2.
Excellent for photographers who shoot RAW and needed some overdue processing tools, but likely an iffy upgrade for someone who just occasionally dabbles in graphics or something comparable.