[Bloody Sam Roberts]

Number 5 and 20 have already gotten the TV treatment. HHGTG TV series on the BBC was the original based on the book. The BBC Radiophonic Workshop radio series was based on that. Though I wouldn't mind seeing a new series strictly adhering to the book or radio series. There have been many more radio shows of HHGTG...the Tertiary series, the Quandary phase, etc.

And there have been several Dune entries on TV that ran on the Sci-Fi network some years ago.

[EveningStar]

From the article:

"With the advances in TV over the last few years, I think it's time for a new adaptation of The Hitchhiker's Guide To The Galaxy. The movie was disappointing and the original series is looking very dated, but the material is still hilarious." – ethantbale

"[Dune is] Game of Thrones in space with complicated and interesting characters. Even the first book could be two or three seasons and there are loads of books. There's a huge universe of world building, great plot, loads of ideas about ecology, religion, fate, myth, and even sword fights." – Lucy G O'malley-Local, Facebook

"I know it's already been a movie and a mini-series, but I feel like the only way to really do it justice would be to give it the full HBO treatment in an ongoing series." – Brendan Anthony, Facebook