It looks like it will be down to three: iOS, Android and Windows Phone7. Although I never used Symbian or MeeGo, I feel sad for their demise. Open source breeds innovation, and neither iOS nor Window Phone are open source, leaving Android to do all the work.
I know, I know, Apple loves to think it breathes innovation–and it is innovative–but Apple still has that drive to dominate that a true open source doesn’t. Look at the lack of Flash support in iOS phones. Open source would never kill support of another product. And yes, I love Windows Phone 7, but Microsoft often times likes to rest on its laurels when it’s won a battle. Just look at Internet Explorer after it killed off Netscape. Not only that, but look how Microsoft walked away from the .lit file format, leaving Microsoft Reader fans to fend for themselves.