reply to floydb1982
Re: YouTube fullscreen not working right I'm usually just a lurker here, but I need to chip in. It doesn't look like the OP is complaining about the aspect ratio, just that the video appears to be playing as the background of the page rather than filling the screen.
Look at the 2 screenshots posted: there's a task bar, title bar, related video, comments section, etc. This isn't about aspect ratio (which Youtube has never messed with) but full screen not working.
Definitely some weird browser issue. floydb1982, try using Firefox or Chrome and see if you get the issue. Maybe try updating your Flash player.