This is odd. Around 1:30am pst (Feb 23 ’09), movies on youtube have stopped working.  As if there was a glitch that has all flash flv being selected instead of the h.264 codec coming up.  I did a quick check on twitter and seems others are having the same issue.  The odd thing is I can sometimes get it work when in edge only. … scratch that, now edge is not working either…  Hmmm..

{update}

I found a workaround..

Go to www.youtube.com and play your videos from the website.  Not every video will work because the search results provides videos whether they are flv or h264. This is clearly a work around (hack) till they get this fixed, but at least you can get your youtube fix.