Despite improved performance, an exceptionally cool and useful Live Color tool, and a more streamlined interface, I can't shake a feeling of disappointment in Adobe Illustrator CS3. The most recent iteration improves on its predecessor, but not in any way that seems to significantly enhance the speed or efficiency with which one works within Illustrator.
Adobe tries unsuccessfully to turn a molehill of interface changes into a mountain of productivity. Nevertheless, the additions are welcome. In many ways, the interface simply provides better visual feedback on where you are in the path-object-group-layer hierarchy. The Layers palette has better color coding for selections. As you mouse over nodes, they enlarge. Isolation mode imposes visual context as you drill down into a group; irrelevant elements successively gray out, and a trail of breadcrumbs appears at the top of the screen. The breadcrumbs provide a very handy way to jump directly to another object without wondering if you've risen too far up the hierarchy.
Flash CS3 integration, but most of that benefit falls in the camp of the Flash designer. Since Flash CS3 handles Illustrator file import much better than the previous version, Adobe has tossed in a few more parameters for the Illustrator file to pass over to Flash. If you define an object as a Symbol, you can flag it as a Movie Clip, set a Flash registration point, and position the 9-slice Scaling guides. Unfortunately, you can't preview the effect the guide positions have on the scaling, which can be quite irritating . At least you can paste without loss from Illustrator to Flash.
Similarly, Adobe has uncomfortably grafted the Flash text-handling interface into Illustrator. In a dialog almost identical to that of the relevant property sheet in Flash, any text block can be defined as Static, Dynamic, or Input. The latter two can be named; assigned an antialiasing scheme optimized for Readability, Animation, with a custom detailed with your own thickness and sharpness antialiasing settings; or limited to device fonts. Dynamic text can be flagged as selectable or boxed, linked to an URL, and have custom character sets embedded. For Input text, you can specify a maximum number of characters.