Strangely enough, I'd say Iron Man. A lot of people I've talked to about the movie were more into Tony Stark's smart home tech than they were into the suit. I distinctly remember one female friend of mine who despises tech talk, asking me all about whether it would be possible to engineer those self-dimming window displays.

Maybe it's not as realistically grounded as others, but it definitely shows people why we do what we do: we like building cool stuff.