As I've said before in my custom views filter handlers tutorial, views is amazing. Today I was writing a custom style plugin. I got the plugin to show up in the list of available formats, but whenever I saved the form, it wouldn't stick.
If you haven't already heard of it, the Theme Developer is a great tool. It works like firebug, but for Drupal. You can click any element on the page to inspect it, and the Theme Developer window will show you what template files and functions were used to render it, and give you suggestions on which files you can edit to affect it. For a newbie Drupal themer, this can be a god-send.