For me it is no contest. It would have to be:
<object width="560" height="340"><param name="movie" value="http://www.youtube.com/v/u6mYGcNgKn8?version=3&hl=en_US"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/u6mYGcNgKn8?version=3&hl=en_US" type="application/x-shockwave-flash" width="560" height="340" allowscriptaccess="always" allowfullscreen="true"></embed></object>