[Plugin: Viper's Video Quicktags] Youtube videos are too small

Adding the shortcode [youtube]http://www.youtube.com/watch?v=Ks7jmfeY3b0[/youtube] to a post using the Youtube button, the videos are showing up small – http://blog.noisegate95.com/archives/1210 in Firefox and Chrome. IE9 shows up just fine. Vimeo videos are perfect placed. Any help would be greatly appreciated.

http://wordpress.org/extend/plugins/vipers-video-quicktags/