If I were to look at it from the business side, It would be, yes guns from the movies but more importantly the video game market. The young crowd is now older and is starting to realize that the guns in the games are real.
Caliber probably would not matter, so the cheaper to shoot 9mm is good for profit. But that being said a .45 and 50 cal should be in the mix. Like others said a gun that can daily use is better.
1911
Glock
Desert Eagle
Kriss Vector
Thompson 45
M4
Revolver