V for Vendetta

The following weapons were seen in this film:

Beretta 92FS Inox

The Beretta 92FS Inox appears to be the standard-issue sidearm of the Fingermen.

Beretta 92FS Inox 9mm

A Fingerman shooting a little girl with a Beretta Inox

A Fingerman in the subway aims his custom Beretta Inox at V (the weapon has a large barrel attachment with some type of flashlight underneath).

Taurus PT92

One of the Fingermen in the opening scene carries a stainless Taurus PT92.

Taurus PT92 (stainless) 9mm

A Fingerman trying to kill V with his Taurus PT92.

Glock-17

The standard-issue sidearm of the police. Glock 17s with flashlights are also used by many of the Fingermen in the subway scene.

A Generation 3 Glock 17 9mm. Note the finger grooves, thumb reliefs, and accessory rail on the frame, which differentiate it from the older model.

Police officer with Glock-17.

Fingerman nearest to the camera has a Glock-17 with an under-barrel flashlight of some type.

H&K G36

The weapon used by the British Army in the movie.

Heckler & Koch G36E 5.56mm

Soldiers with the H&K G36 facing a civil rebellion.

H&K USP Compact

Used by Dominic throughout the movie; has a stainless slide.

Dominic threatening V in the Jordan Tower lobby

M4A1

Colt M4 Carbine with standard (not the LE) stock - 5.56mm

Guards at Larkhill Camp with M4A1's

Colt Python

A robbery by a man with a V mask and a Colt Python.

"Disgusting!" Creedy executes the helpless Chancellor with a Colt Python magnum.

Neither of these guns have vent ribs above the barrel, so it's far more likely they are of the Rossi or S&W family, and not of the Colts, with the exception of the King Cobra.