You could draw comic, art work, drawings, architect houses and what not.
Also using the 3d features create sick web 2.0 looking stuff, this is used by many Graphics Designers.
Almost everybody use this, by everybody I mean every artist.
Vector is all about geometrical points, so that's why it gives clean edges as opposed to the Pixel stuff Photoshop!
Taken from the Official press release from the site info about the application, read this below one.
"Design with Powerful Creative Tools
New stroke and paint capabilities anchor Illustrator CS5. Designing with strokes is now more powerful and flexible than ever: users can control stroke width at any point along a path, align dashes to corners and path ends, add accurately placed arrowheads directly from the Stroke panel and control how brushes stretch along a path. Painting with vectors now resembles real-world brush strokes with the new Bristle Brush, which offers breakthrough control of painting. Using this highly anticipated tool, designers can set bristle characteristics such as size, length, thickness and stiffness, as well as brush shape, bristle density and paint opacity, for simulated life-like blending."
It's a real great application you can explore your creativeness extent through this app.
