Very true. Hans Zimmer particularly has a very distinct style, and one that fits military themes.
It's one of the things which MW2 does indeed get right. They paid for a great soundtrack and they got it.
In my opinion, Hans Zimmer is indeed best suited to military themes. He composed the soundtracks for Crimson Tide, The Rock, Broken Arrow, The Peacemaker, The Thin Red Line, Gladiator, Black Hawk Down... the list goes on. And they're better soundtracks than his non-military soundtracks.