Ok so a few cool suggestions.
I haven't finished the series but I finished the one where they build planes last and I have the rest. Very easy to convert to film.
I also think
Michael Cobleys Humanitys Fire series would convert really well to a film. Lots of cool visual ides, nice and readable with tonnes and tonnes of alien species.
Nivens Ringworld as mentioned, although I do think the lack of an actual ending in a traditional sense might annoy modern sensibilities and they might change it.
I think
Vinges Fire Upon the Deep would be brilliant, huge galactic level threat, cool aliens and a space chase. There would be the medieval analogue world populated by dog pack analogues and then the high tech space place. There is a particular disaster scene in that book that would be epic on screen.
Clarkes Rama would be nice to see. Might work better as a mini series though.
I do think
Sandersons Mistborn series would adapt well to film, the visual aspect of flinging and using coins and metals to push and pull and for enhancements could easily be shown and would look pretty good. To be honest an ambitious studio could even use that to setup the second set of books, use the same actor with a different haircut and link them ancestrally in some way. As an aside I always though that the Necromunger bad guy from Chronicles of Riddick looked how I imagined the Lord Ruler from Mistborn would look.