Give Sabaton a shot. They are the breakout band from the power metal genre over the last few years and the singer doesn't have the high vocals most of you would hate from that genre.
All of their songs are about military battles, from all sides of all conflicts. Kind of like a metal history lesson. Lots of anthemic, singalong stuff.
They are actually my favorite band of the last two years. Someday I hope to see them in their hometown (they host the yearly Rockstad Falun festival in Sweden).
Try Ghost Division, one of their best and heaviest songs: