One thing that really annoyed me about YouTube was its inability to get videos to go truly full screen. The videos were always locked within your browser window and never took up the full space of you monitor, not to mention the fact going full screen restarted the video.
Now YouTube has solved this and offers a fluid full screen option. The full screen button now quickly resizes the video to take up the whole of your screen and you just simply press Esc to exit.
The full screen mode works in a very similar way to the StreamCast Player I talked about a couple of days ago.