i like more war lyrics (Battalion(belgium), Bolt Thrower, My darkest hate...) and philosophic ones also some satanic and gore i don't really care about those
afuckingmen, otherwise if I had to choose a type of theme, i would choose norse mythology and ancient cultures like atlantian culture(see The New Mythology-V by Symphony X who talk about the corruption of atlantian society, very random, but who gives a shit, the music is quite awsome)