alt Hacker NewsCE 6 doesn't get enough love. It was an amazing OS that had a tiny runtime and a tiny on device foot print (it could get under 16MB iirc).
Too bad the tooling around it was so bad. I should do a writeup of why, it is an interesting case study in how poor extendability of tooling can hurt an entire company.
Part of the reason CE 6 didn't get much love is that everyone had been burned so many times by all the previous CE releases -- not to mention that CE 6 was far too late!
In the end, though, it was better than Mobile, but hindsight is 20/20.