Season 2 has already been announced (
http://www.tvshowsondvd.com/newsitem.cfm?NewsID=4293 for the art, follow the link within for more on release date, episodes, etc). Judging from comments on the web (most of them non-comics sites), demand for this series is very high indeed.
I'm hopeful for the Alyn serials, based on the release of the two Batman serials. What I'm really looking forward to is the Spy Smasher serial.
Like I said before, with the release of Superman Returns hopefully this will prompt them to cash in on it by releasing the serials.
I also hope that all the old Fawcett serials are release as well, I have the Captain Marvel one, I would like to have all of them.