Now that WordPress 2.8 has been released, it really would be more useful and helpful to get a big list of tips and tricks that addresses several new things in WordPress 2.8 and helps to learn or tweak the new features, these tips come from several users who have been using WordPress 2.8 for sometime and have contributed with several posts that may help you make the best out of the latest version in WordPress.
- WordPress Codex – Version 2.8
- Custom Taxonomies in WordPress 2.8 – Justin Tadlok
- Build A WordPress 2.8 Widget – WP Engineer
- WordPress 2.8 and the body_class() Function – Nathan Rice
- Authentication in WordPress 2.8 – Will Norris
- 10 Things to do before and after installing WordPress 2.8
- Getting Started With WordPress 2.8
This is non-exhaustive and I will keep updating it regularly, if you have any resources please do feel free to add to the list by commenting.
[EDIT] WordPress 2.8 hides the plugin folder by default (SecuObs)