For anyone interested in sci-fi war stories, I'd recommend Mobile Suit Gundam Unicorn just to get them started. It has all the pretty animation that looks great on blu-ray while still having a captivating story and characters. Also Mobile Suit Gundam 0080 War in the Pocket is a great choice too. And considering War In the Pocket is only 2 hours, it's not really a waste if you don't like it.
+1 to this. UC Gundam doesn't get enough love in the west. Too many people think of the boy band (Wing) when they think of Gundam, instead of the war stories in the Universal Century time line.
0083 Stardust Memory and 8th MS Team are heavily action packed and not too long either. Wish they'd animated the New Decides/S-Gundam series -it'd be awesome.