If the Tallarn are in the book, or you just want to run a desert world campaign, there's always Lawrence of Arabia.

I know it's already been mentioned bet; Starship troopers should be required viewing for Imp guard players!

Oh, And one I'm surprised I didn't see mentioned: Patton.

"Now I don't want to get any reports that you're holding you're holding your position. We're not holding anything! We are advancing! We're gonna grab em' by the nose and we're gonna kick em in the ass! We're gonna go through them like crap through a goose! We will pull out their living guts and use them to grease the treads of our tanks!" All you need to add is "For the Emperor!"

Tobruk.

How could I forget I.M.P.S. The Relentless!:-

http://www.youtube.com/watch?v=JUbmYfAF2i4

http://www.youtube.com/watch?v=hvubKf3BK04

And TROOPS for that matter:-

http://www.youtube.com/watch?v=bocmVZXXY8w

 I've always thought it would be cool to have a game run along the lines of "The Last Samurai" where some guardsmen are brought in to train up an army from a world new to the Imperium.  You could either have the guards stay with the governmental forces and have them do battle with the planet's outdated but super awesome warrior culture or arrange for a way for the heroes to end up appreciating and coming to work for the other side.

Oh, and don't forget "We Were Soldiers." 

LegendofOld said:

The "Super awesome warrior culture" could end up being either recruit potential or the seeds of a new chapter of Space Marines. I can't think of a chapter based on the Samurai yet. Perhaps it's due! (Btw: before I get flamed, I know that the white scars are Asian themed but they are Mongol styled rather than Samurai. They would make an excellent Progenitor chapter for our new "Rising Suns" chapter) Perhaps their chapter ability would go beyond the basic "Know no fear" to being truly "Fearless!"

Radwraith said:

I'm afraid /tg/ over on 4chan beat you to it. javascript:void(0);/*1334384215350*/

Cool! I did not know about that! And already statted out for DW! Interesting!

The most accurate depiction of modern troops in modern combat, the HBO series Generation Kill, about 1st Marine Recon during the invasion of Iraq.  Some of the actors are the actual Marines that were there.  I should warn you, they pull no punches with the language and dialogue, so if you are easily offended, don't watch this. 

The Pacific, about Marines in the WW2 Pacific theater, done by the same people that did Band of Brothers, is good too.
 

Act of Valor, the new movie that just came out about Navy SEALs with actual Navy SEALs is good too.  The acting got slammed by some people, but like I said, the main characters were played by real Navy SEALs, not professional actors.

My additions to this thread would be the following:

A Bridge to Far

Cross of Iron

Stalinggrad

Saints and Soldiers

Das Boot (maybe a bit to much Imperial Navy)

Predator 2

The Winter War

Baradiel said:

There's a movie called Deathwatch, a horror movie set in a WWI trench. Would be awesome to use as inspiration for a chaos-themed adventure. A good movie too.

I'm surprised nobody mentioned "Blackhawk Down" yet. You could run a mission based on that movie:

"We got a Valkyrie down, we got a Valkyrie down"...

I'd like to think we'll play/run something progressive and introspective, but the reality is there's gunna be a whole shitload of Rambo somewhere in the mix ;)

MKX said:

Progressive and introspective? In the Imperium? Good thing we're not playing DH! "Lord inquisitor? Sir, I'm uncomfortable with the Idea of using torture to gain information on that heretical cult. Perhaps they are just misunderstood and not Heretics at all! Inquistor: I understand my son...<BLAM!>

Of course the results might be much the same if you fed a similar line to your Comissar!