One source I had missed for information: Apple. They have some interesting stuff on their Final Cut Studio Resource page.
If nothing else, it’s worth going to get the Alpha Transitions, Color Looks and Compressor Droplets that are available for free.
The Alpha Transitions are very cool. After downloading them, they have to be "installed" and used in a particular way; this tutorial explains how to install and use an alpha transition: Using the New Alpha Transitions in Final Cut Pro 7.
Even if you don't like the examples Apple has provided, they show you how to use Alpha Transitions, and might get you wanting to create your own using Motion.