I'm not a fan of 2010 (either the film or what Asimov wrote) because I think with the why-did-HAL-go-mad thing, the question is better than the answer. Contradictory programming is boring as an explanation. I prefer my theory - ie that as HAL approached the monolith at Jupiter, intended to kick man up the evolutionary spectrum, HAL himself started to evolve into a new level of machine intelligence, and could have superseded man.

Kubrick was absolutely right to keep it ambiguous, stripping out explanatory voiceover and whatnot. It is so much more powerful without it.