I finished watching Kure-nai today, such a good show.
Code Geass (mecha), Fate/Zero (action), Steins;gate (sci-fi), Gyo (sci-fi, "horror"), and I was just about to say Cross Ange which is in my opinion really great mecha/action anime (even though most of people claim it's a bad show huh) but then I realized it has shitloads of fanservice but I still think it's worth watching. Kurenai is also a good show without any fanservice, it has some action in it too especially in the second half. And Kara no kyoukai maybe?