Yes, one of the promise of .NET was that write once, run everywhere. Yes, Java has managed to actually pull this out. Than comes Xamarin. These guys (with Miguel Icaza, who I happen to know in person since 2001 probably – I still has his business card from that time :D) are just AMAZING. Write once as a portable library, and run as a windows store app, a wpf app, a web app, a windows phone app, an iphone app, an android app, a mac app – possibilities are just endless.
So come Nokia, creating Nokai X, which happens to be an Android phone, but with windows phonish UX, and with Xamarin that means… I can run C# on Nokia X, and port my windows phone app to Nokia X like a breeze. So, would I buy a Nokia X, X+ or XL? I don't know, but the possibility is there.