I quite liked the sad, brutal Super, an indie superhero flick from James Gunn (Slither) that was better than X-Babies, Captain America, and Green Lantern combined. Part of that like was thanks to its opening credits sequence—a low-fi version's above, and the excellent Art of the Title just examined it in pretty great detail. Like this bit, from an interview with one of the designers behind the sequence, Mike Owens:

I always approach animation musically. A lesson I learned from Tom & Jerry cartoons. The music scores in those cartoons were composed after the animation was complete. The director would time out the story and the action on bar sheets, which are essentially the bars used in music notation, to determine the tempo in frames per beat. Working at 24 frames per second, marking a beat every 8 frames sets up a faster tempo than a beat every 16 frames, 16 frames per beat is faster than 32, etc. Once tempo is established, there is a rhythmic outline for how the action is paced. This template can be used to determine when a foot hits the ground in a walk cycle or when a character strikes a pose or reacts to another character. You have an exact frame to place an accent. You can build tension by holding back on the accent, letting beats pass then hitting it on the off beat to startle the audience. Or you can change up the tempo to change the tone within the story. A character may be dragging along at 32 frames per beat, feeling lethargic, tired, depressed when suddenly he unexpectedly finds a $100 bill on the sidewalk. Suddenly there is a bounce in his step as he happily struts down the sidewalk at 8 frames per beat.

It's worth a read. And a watch.