Battle Of Mobile OS
Symbian is a very good OS and has a strong growing market sponsored by many device makers, but Windows Mobile is also a very good platform. Since mobile devices hardware has evolved a lot in the last years, chances are a new OS battle will happen soon.

You can read an in-depth article regarding this issue here: http://mobileopportunity.blogspot.com/2006/11/symbian-unloads-uiq-and-mobile-apps_09.html. And don't stop at the end of the article, but go on for the comments, too. It's definitely worth it.