Originally Posted by EvilCheeseWedge
I can think of two right off the top of my head...
Sabbath - War Pigs - it's about politics, as opposed to do either ripping off a poem or movie, or merely relating what actually happened.
Queensryche - Surgical Strike - about how we train ("program") soldiers, pretty interesting, as it's about warfare, but not a specific war
Yes and yes
As for Megadeth and Metallica, hell yes. Slayer used to write good ones too.