Sad news for HTML5, while Ogg Vorgis/Theora were not necessary to make HTML5 work, a standard codec is needed to make some part of HTML5 usefull – the part I worked on for WebKit/Gtk+. This point has been repeated over and over: all browsers implemented HTML5 needs to have a common codec.
While there is no default image format in the HTML* spec, we were lucky nobody ever used their patents against JPEG. In fact, it is most probably because of said patents that Apple and Nokia were reluctant to include Vorbis/Theora on their OS or their phones.
Someone has to fix that patent system!