An interesting thing to note is that some Allen Bradley PLC's have DS80C320's in them!

Another item of note is that in a lot of cases, embedded programming is done by engineers which is the case with myself and most of the other people I know that do this kind of stuff - I don't know of many programmers that can cope with the low-level details involved in small microprocessor based controllers since they don't have the electronic background. In my case the programmers do the PC side of things and I do the microprocessor side of things. I would suggest that anyone contemplating forming a career doing embedded systems that they have a wide exposure to different processors - not just 8051(a good start though) and different operating systems from simple task switchers to full blown ones like Windows and Linux.