I still think the AmigaOS/MorphOS could be a nice niche embedded system. I so think that, in fact, I will probably use one of them in my next project (a home automation system).
Why use an Amiga-based system?
* I like the Amiga spirit!
* Supports smaller, innovative companies, good for the economy.
* Really small, efficient and fast operating systems.
* "Secure" (different from mainstream OSs, unexploited) and virus "immune".
* Usually lower power consumption hardware, good for the environment.
* Usually cheaper than a Windows system (Windows is payed separately, and current versions usually need better, more expensive hardware to perform well).
MorphOS goes on a very interesting path here, complying with almost all points (assuming it will run on the "smarttop"). AmigaOS is still relatively expensive, and so is it's present hardware (Sam440), but that could be easily fixed now that Hyperion have nothing to hold them back.
No, I don't think the Amiga can go on battling Windows or MacOS X, but it's really interesting from the embedded/dedicated point of view.