I'd love them to get around to attempting Ubik - it's a shame that Gondry abandoned his attempt.

In terms of ambiguity, surely Blade Runner is a prime example of ambiguity and the dichotomies between real/fake, light/dark, salvation/damnation, hunter/hunter etc. There's also the very significant portrayal of Roy Batty as both the villain and a Christ-like figure (e.g. nail in his hand, confronting his maker and both kissing and killing him).