Danny Piccirillo has posted an awesome Lucid post-install guide on his blog that covers a lot of cool stuff that you can do with Ubuntu 10.04 after installing it, including a great list of quality applications and easy instructions making use of apt URLs.
Check out his table of contents to give you some idea of what he covers:
- Managing Applications
- Eye Candy
- Desktop Functionality
- Web Browsing
- Multimedia Creation & Editing
- Multimedia Playback
- Time Management
- Donating CPU Power
- Images and Publishing
- System Utilities
- Security & Privacy
- Proprietary & Restricted Software
- Explore, Customize, Personalize!