Mark Jaquith recently performed a scan on a local copy of the WordPress plugin respository and was able to generate a list of basic quoted string shortcodes within the plugins. The list looks like it could go to the moon and back with some funky looking shortcodes that are not very descriptive. Mark notes that there has been some discussion on whether or a not, a directory should be built and published which notes all of the shortcodes in use from all plugins in the repository so that plugin authors can check and see if their own shortcodes would conflict with any other plugins or perhaps, make theirs compatible with another.
While I don’t dabble in as nearly as many plugins these days, I can say that I’ve never gone through the experience of dealing with a shortcode conflict. If you have, I’d love to hear your story.