Hey, It's That Guy!: Paul Giamatti, J.T. Walsh, and Siobhan Fallon (you know, the redheaded chick with the droning voice that has made a career of "Hey, it's that girl!" roles) as the hostages, Paul Guilfoyle as the detective whose murder sets the plot in motion. David Morse, who plays the gung-ho SWAT captain Beck, has made a living out of playing no nonsense police and military figures. (See his roles as Major Baxter in The Rock and Brutus Howell in The Green Mile for starters.)
What Could Have Been: Initial plan was to have Spacey as the hostage taker and Sylvester Stallone would have been the opposing negotiator.