Detective Conan 1 - 300
One of the longest airing anime series of all time, number 2 on the list of the longest anime series ever created, is Detective Conan - or Case Closed as it's known as internationally. I never planned to pick up this series, yet decided to watch the first episode on a whim, and since then I've been captivated. The main character is Shinichi, a highschool detective who gets drugged by a mysterious organization, in the first episode, after solving his first case in the series.
Detective Conan is something extra. Though the plot itself progresses awfully slowly outside the first few episodes, each case is in itself a work of art. The creativity and detail with which crimes are committed, and the clues and deductions that help Conan (along with many other helpful characters) solve each crime turn this into one of the most thought-out series I've ever seen. I tend to like fast-paced action better, so I suppose the exception proves the rule. This just isn't like most detective fiction I've seen - it's on an entirely different level.
So, I started watching the one episode and suddenly I'd watched 300. There's still quite a way left to go till I catch up, but considering how minimal the plot progression is, this isn't a serious you need to rush with. You can watch each episode, or each two episodes (when a case is composed of a couple) and get just as much out of it as you would a movie, and it's refreshing how it doesn't require continual watching. A certain day. A certain time. Every week. Like most series do...
Apart from the series, there have been plenty of movies over the years, each one not very different from specific cases, but with a noticeable raise in animation quality and complexity of the scenario Conan's about to solve. There's also the shot mini-series starring Kaito Kid (who appears occasionally in Detective Conan, more as a challenger than a real enemy). Even though he is a thief he never gets caught either. And of course there's the Manga! I was given a few books this year, and was surprised to see there were a few extra comic strips included in each one, featuring the cast being crazily creative and morbid and occasionally (fictionally, of course) killing the author. Who apparently had some trouble sleeping while working with some especially brutal cases.
All in all, it's a series worth watching, one that stands out from the mainstream by particularly not doing that. You could say it dwells in the shadows, in the underground of anime, steadily growing and taking over yet unknown for the vast majority of those who think they have their genres all figured out. I'm hoping to get some more of those manga books soon. JUst a few, maybe. A hundred or two.