UPDATE March 17, 2009:
For an easy way to generate rounded corner SVG files, see my border-radius for all! post.
The recently released Opera 9.5 alpha is known for it’s improved CSS support, but what excited me most was the ability to use an SVG file as a background image. Why is this great? It allows for all sorts of neat things. Small file scaling gradients, multiple raster images, even animation!