the coolest ending I think would've been, ****SPOILERS****
after the shoot out, Foxx is the one hit and falls over dead, and then Vincent walks over to where Jada is sitting, have a shot looking up at Vincent with his gun pointing at you as if in Jada's point of view, then fade to credits. Now that would be kick ***!!!
okay here goes. Vincent is in the building searching for Annie, and he finds her sitting there behind her desk cowering away. Vincent slowly walks over taking his time and pulls out his pistol and is about to shoot her when she pulls a matrix move, doging the first bullet and tripping Vincent, as he fires another shot into the ceiling. she then takes a chair and throws it against the window breaking it and she jumps out (in slow-motion).
As she is falling Vincent peers over the edge and mutters "oh shit" and jumps out after her while shooting, he manages to hit her head and as they fall Vincent deploys a parachute and escapes while pressing a button that nukes the building. After that he lands and snipes Max making a clean getaway in the Batmobile!
But seriously the only thing I would change is that they at least drag Vincent out of the train before they left. It is just plain evil to leave him there on the train dead going around half the state!!