When I installed 12.04 I also added Ubuntu-restricted-extras. I decided to try accessing flash content in Firefox without the Adobe plugin, and I wanted to experiment with streaming video directly with VLC, so I removed flashplugin-installer. I thought everything was still working on YouTube when the first video played flawlessly, but it seems to be hit-and-miss; I'm not sure why some play while the rest give me the "Adobe Flash Player required for video playback" message. Those that do load look better and allow a smoother browsing experience.
Can I get videos to play consistently without the Adobe plugin?