@AC (Maybe)
If it runs on whatever gives it the best performance/battery life I think it'll do well. It's not about the desktop, it's about the applications.
The iPhone / iPod Touch SDK has revealed a whole new cottage industry of developers, and the App Store has proven itself a great delivery platform (even if iTunes isn't very good for discovery).
I'm quite fond of the iPhone's desktop and apps myself - it's nice to not have to think too deeply about where things are; a feeling shared by the majority I'll bet. I have my laptop and desktops for that.
If it is Touch based, the only thing I can see that will kill it for that reason is if they fail to allow background apps.