I am just so absolutely besotted with procedural methods. I am currently playing with procedural floral patterns. This one is cooked up from about a dozen parameters -- number of petals, length, radial noise, petal width, petal attenuation function... it goes on. It's fun to explore the parameter space and see what you can come up with. It is implemented as a Renderman displacement shader.
I would really like to do the same in true 3d, though that is a much more complicated problem. I'm thinking of generating the base geometry as stream-surfaces based on particle simulations. I dug up a particle system I wrote a couple years ago, and it is pretty darn good -- fast and flexible. Finer detail could be provided through displacement shaders.
I was considering using floral patterns like this for a sound-reactive animation I am working on, though it just doesn't match the music, which is jangling and percussive. But then, maybe that would be cool.