Zuken, I'm really not a fan of thrash metal, but the song you just linked: 'Arttu Wiskari - Tuntematon Potilas' -that was nice. I don't speak Finnish, but I wish I did! I love the language. The song sounded nice, and I read someone's translations of the lyrics. I have a few Finnish songs in my collection, and my favourite bands are Finnish.
As for the other songs suggested and posted, I'll be sure to take my time to go through them at some point. My taste in music is very varied, and even if something isn't exactly to my liking, I can still appreciate a song's meaning.
A suggestion of mine that comes to mind right now: 'Our Solemn Hour' by Within Temptation. It's a song about WW2, though it makes general reference to man's tendency to perpetuate war, and forget lessons of the past. Most likely not to most people's tastes here (Symphonic rock/metal, if you feel the need to classify), but I really like it and think it's worth a listen- she has a beautiful voice. I think it conveys well it's message, and the sense of despair. Here it is: Our Solemn Hour (W.Tempation) - Lyrics - YouTube