One of my groups ran a campaign set in the post-apocalyptic future of the Terminator universe, using the d20 Modern rules. One of the best games I have ever been in.

Next with that group, if we can find a good rule set that works for us, we are thinking of a Ghostbusters campaign based off of real-life ghost stories and legends around the Chicago area. Ideally we'd like to adapt the d20 Modern rules, but if that's not feasible then we might try another system.

For less direct influences, my current D&D campaign incorporates some elements of the Suikoden video games, with regard to establishing a castle and recruiting a bunch of people, at least. Unfortunately my players haven't been too good at recruiting so far.