Songbird: the Next Big Thing?

Songbird will be released on December. Will it be the promising integrator of digital media sites?
Certainly, it's built on top of XUL, which is the ultimate flexible framework for building great applications. I wonder what playback engine are they going to use.

Songbird will be released on December. Will it be the promising integrator of digital media sites?
Certainly, it's built on top of XUL, which is the ultimate flexible framework for building great applications. I wonder what playback engine are they going to use.