Grendel_Khan
Hero
I'm going to go with GURPS because it's the most realistic game (potentially) that I've got experience playing. It's on a sliding scale, you can certainly tweak the rules for a more cinematic experience, but if you want to crank up the realism it's certainly possible. One of the simplier ways they do this is by dividing skills into different categories based on how easy they are to learn. Firing a gun might be a physically easy skill whereas nuclear physics is a mentally hard skill meaning it's going to cost you more points to get that physics skill to the same level as the gun skill in most cases.
When I was a teenager, I loved the fact that GURPS had all sorts of system mastery riders and exceptions, like that guns might be physical easy skills, but firing without taking an action to aim meant you had a snapshot penalty (-4 iirc). Meaning so long as everyone burned a turn before shooting it really was very trivial to hit someone at close range, but then, ain't nobody got the time for that (especially if it's going to be another half-hour before you get another turn).
In my old age, I have no patience for that sort of thing. Or for the need to drop a half-point into a slew of skills just to simulate being a barely functioning human—sure, there are default rolls, but they're brutal. But for those who are into that level of detail and futzing, GURPS is almost impossible beat.