Good start- I'd definitely be looking for something with a 'modern' kydex sheath
The only thing going against the 'traditional' Kabar is the carbon steel of the blade- rust's a problem.
Now the 'next gen' models with the kydex handles and stainless blades ARE great knives, but I feel they lose the toughness of the originals.
Further, while the Kabar was originally designated a 'fighting knife', it's most definitely an all round utility knife....I'd have thought the USCM grunt, used to dropships and fast recycles back into orbit, would be willing to sacrifice a bit of utility for the sake of a more 'martial' blade shape

Also- as the USCM are an 'elite' unit, there's generally a cachet around carrying a dagger going back to the SOE and Commandos of WW2.
The Marine Raiders of WW2 carried a version of the Fairbairn-Sykes dagger instead of the Kabar- which I feel is more in keeping with the standard operational mentality of the USCM as portrayed in the movie
(
http://en.wikipedia.org/wiki/United_Sta ... r_stiletto)
So: My take would be one of the following:
A Microtech ADO- the double edged, half serrated version
http://www.microtechknives.com/knives-2/our-knives/As it's very modern and very obviously not for peeling spuds...One piece forging and TiNi coating
Then for those wanting to hark back to bygone days- A Cold Steel Chaos- a modern take on the WW1 Trench Dagger, complete with skull cracker pommell.
http://www.coldsteel.com/Product/80NTP/ ... _Edge.aspxI've got on of these and it's bigger in every way than the Gerber Mk2, but not as finely balanced or as well made.
Then maybe something like the now discontinued SOG Desert Dagger as another choice