Having given several presentations on CS5 and seeing how people are reacting, it’s nice to get some perspective on what others think are the cool features of Illustrator and not just my two cents. So here they are.
Need to create a complex shape but lack the pen skills necessary to do so? Use the new Shape Builder tool to combine objects. Simply select the objects you wish to use then drag the Shape Builder across them and viola! Instant shapes!
The new Artboard Panel allows you to name and organize your Artboards, similar to Layers. If you are saving files that use Arboards, like .eps, individual files will be named using the Artboard names.
Use the Draw Behind feature to ignore stacking order when creating images or use Draw Inside to create an instant clipping Mask.
You can now vary your stroke width using the Width Tool. Adjust your stroke as needed and change back using the presets available in the options bar.



