Another favourite of mine, Code Geass is set in a futuristic Japan and follows around Lelouch vi Britannia, a high school student who looks after his blind younger sister Nunnally. Whilst living a peaceful life surrounded by friends and family, things soon change when Lelouch becomes entangled in a battle between the Britannian Army and the Rebels, during which he meets CC, an unusual specimen who grants him the power of the Geass. This ability allows him to order a person to do a certain action without their defiance, which he learns can only be used once on a person. He then chooses to use the Geass to make the world a better place for his sister by overthrowing the Britannian Royal Family. By doing so, he creates a persona known as Zero and teams up with the Rebels to put his plan into action.
But with a mysterious rebel leader comes its enemies, including Lelouch's best friend Suzaku who is part of the Britannian Army as he joins the battle against Zero. This also means we see more of the Royal Family as the plot thickens, and the reason why Lelouch wishes to overthrow the Royal Family unravels. These combined make for an anime full of action and emotion, and robots. Yes, robots. These come into play during battles as they are used by the Britannian Army and the Rebels.
What's more, if you enjoyed the first season as much as I did, you don't want to wait around to watch the second season if you haven't seen it yet. This has a slightly slower start than the first season, but it is just reintroducing you to the characters and setting the scene for the aftermath of the season one's ending. Don't worry if you're unsure as to what happened, because there are flashbacks to show what happens between the two seasons.
Code Geass is one of the anime that should be on your "must watch" list. It has plenty of action mixed in with the deep story and variety of characters that also have their share of the limelight (well the main ones do), with a soundtrack that fits perfectly.
A high school student finds himself fighting against the Britannians who have taken over Japan after gaining an ability known as the Geass
Anything else?: The ending is so emotional T-T