Mood music depends on the way the game is going.
If I'm in a defensive war, I almost always queue up Heather Alexander's rendition of "March of Cambreadth" if it gets intense (don't know if it's an original song). Hard to go wrong with a war song with "How many of them can we make die!" in the chorus. Of course, it's not nearly period with talk of axes and broadswords. I queue up the rest of her stuff when I'm not in combat.
For offensive wars I usually queue up Wagner. Scary that it speaks to my German heritage at times
I usually start the game with Kitsch In Sync's "Monkey and the Hitman" because it's a bouncy little synth-heavy tune that gets me hyped without triggering any bloodlust.
Bad (inintentional) pun, but I tend to use Meatloaf as a filler. Queen's albumn "A Kind of Magic" also fits in rather well.