Ouran High School Host Club
After commoner honors student Haruhi Fujioka stumbles into music room #3, she is flung into a whole new world in the already unfamiliar environment of Ouran Academy, a ritzy academy for the children of the rich upperclass families of Japan. In music room #3, she discovers the school host club, a group of beautiful boys who spend their afternoons entertaining the ladies of the academy. Upon her meeting this group, in a startled attempt to leave she knocks over a priceless vase and finds herself in debt to the host club.
I know this thread hasn’t been posted in for ages, but I thought I’d add a series I’ve liked that hasn’t been mentioned here:
Ergo Proxy 2006 (Sci-fi/Crime, Complete) Link: IMDB
Set in a post-apocalyptic future where humans and androids live together in isolated societies (referred to as domes if I remember correctly). This particular series builds upon a series of murders that leads the protagonist on journey to better understand the society in which she lives, those she meets and herself as well. This anime takes on a very dark (gothic) style which really attracted me; much like the original FMA and Batman: the animated series. It has thriller elements (keeping you guessing a lot of the time), beautiful artwork and highly in depth character development. On top of all that, the theme song is awesome! I love the intro video heaps! All in all, I believe it’s a must see. It’s different from the mainstream anime that’s all bright and colourful. It’s a nice change and something that you have to try! 
Darker Than Black 2007 (Sci-fi/Fantasy/Action) Link: IMDB
This anime also adopts a relatively dark tone. It’s about a strange gate and these superhuman beings that begin to appear as a result of it. There is so much plot development that you have to watch it to understand it. The second season takes it even further to explain the story and unfolding events. What drew me to this anime was the similarities in concepts to that of the Bourne Trilogy. Those of you that liked the Bourne series and don’t mind the whole animated/sci-fi twist to create this… will really enjoy the series. Again character development is good; plot develops thoroughly. Has good comic elements in between to give the story breathing room whilst maintaining the flow. It’s another must watch by me. 