i always always fond of the openings to American Beauty and Office Space.

A opening, I can't explain why I love, is Silence of the Lambs. Clarice Starling running in the woods, struggling on the obstacle course and suddenly she gets called in to see a boss. But I think it's an director's opening. Wasn't in the script by Tally. Would be difficult to write stuff like that.

One of my favorite opening scenes, is "The Usual Suspect" the barge scene. I think it really sets the tone for an epic tale to be told. It is a great way ti get the viewer "into" the film.

@TC JAKOBSEN: We've analyzed in one of my online screenwriting classes the change of the opening scenes in Silence of the Lambs from the script to the movie. The big reason for the change is pretty obvious, I think: As opposed to showing Clarice kicking ass and taking names in an FBI training exercise (the script), director Demme opted for a 'soft' opening - Clarice running on an obstacle course, called in to see Crawford, making her way to Crawford's office - to heighten her status as a rookie / underdog.

The opening credit sequence accomplishes this in two ways: (A) By not showing Clarice kicking ass and taking names; (B) Reinforcing visually with virtually every shot a sense that Clarice is a FOOW (Fish Out Of Water), on the run, against the flow:

* Obstacle course: Clarice running through the woods (theme: chased / chasing something), the wood symbolic of our unconscious state (Clarice's nightmares), overcoming obstacles (pre-sages her immediate future with the Buffalo Bill case).

* Walkway shot: All the foot traffic is headed right-to-left; Clarice is the sole person moving left-to-right (FOOW).

* Same with her heading downstairs w/ everyone else heading upstairs.

* The elevator: Clarice the only woman, the only person not dressed in red shirts, the smallest person in the elevator, all underscored by the men staring down at her as the door closes (FOOW).

* Hallway to Crawford's office: In her sweat clothes amidst all the suits (FOOW).

* Crawford's office: As she stands waiting, she turns to see wall full of Buffalo Bill news clippings, gruesome images of dead women, conveying that she has entered the case mid-stream, and will have to play catch-up.

Per your point, it would be difficult to write that and convey anything resembling the psychological effect of the filmed version. And one can't blame Tally for instinctively going after a kick ass opening in his script: His job, in part, is to garner interest of talent, and it's more likely talent would respond to a kick ass opening.

But the filmed version works much better, in my view, in making Clarice more of an underdog, and therefore gaining our sympathy / empathy.

An opening scene that has always stuck with me is the croquet scene that starts off Heathers.