CSS3 is awesome. It allows you to easily make your website stylish, without having to muck about in photoshop. Without images, the pages load faster.
Some things CSS3 allows:
- Color Gradients
- Shadows
- Rounded Edges
Here are two awesome tools that generate cross-browser CSS3... use them!
http://css3generator.com/
http://www.colorzilla.com/gradient-editor/