I was extremely happy when Case Closed (detective conan) came to Cartoon Network so many years ago, and so very sad when it was canceled after only 50 or so episodes.
Basically Case Closed (detective conan) is the story of Jimmy (Shinichi) Kudo, a famous high school detective and devout follower of Sherlock Holmes, that is poisoned by the mysterious "Black Organization" and becomes the child detective Conan Edogawa through a side effect of the experemental drug he was poisoned with. After moving in with his childhood friend and love interest (Their first date happens in Episode 1, before Jimmy gets poisoned) Rachel (Mori Ran) and her father Richard Moore (Mori Kogorou), Conan begins to solve cases, using Richard Moore as a puppet (after being knocked out by a tranquilizer dart, and using a voice changer to sound like Richard) as he attempts to find the black organization, and restore his body to normal. All the while, Conan must keep Rachel from learning the truth of his identity, or risk her and her father being eliminated by the black organization.
The formula for Case Closed is basically 30-50 episode spans of Conan solving regular cases, as his relationship with Rachel (His relationship with her, in the form of Jimmy) begins to degrade due to their distance, and his relationship with her as Conan grows, with an episode related to the black organization every now and again. After 500+ episodes of the series in Japan, only about 20-30 have had any relation to the black organization, so when thinking about buying this series, I'd warn you that you may never get to see the end, unless you speak Japanese (I do) and have a friend that owns every single Japanese episode on DVD (which I also do). Overall, Case Closed is an at-times endearing series, with good mysteries for the first 200 episodes or so (at which point they all kind of blur together. There are only so many ways someone can get bumped off, and only so many possible motives for someone to do it) The only problem is that I doubt Funimation will be dubbing any more episodes (please prove me wrong Funi..) so set 3 or 4 or whatever might be the last they ever release, when in fact they could release 20 sets and not reach the end of the series. The Black Organization is a truly worthwhile enemy, despite this being a "For kids" anime (considering it's 10 years old now, anyone that was a kid when it premiered, is now out of highschool probably. The stories have always been mature, but they are getting even moreso now. Yes, that's right, it's 10 years old, 500 episodes in, and it's STILL GOING IN JAPAN. You may never see the ending if you prefer dubs and don't speak Japanese).
This is the cheapest Detective Conan has ever been in the US, and I believe it's finally time for me to purchase it, considering that I've been a fan for many years now, and have thus far relied on my friend and on funimation TV reruns to get my Conan fix. Case Closed (Detective Conan in Japanese) is a gigantic investment as far as time and money goes, and considering that there are entire 26 episode animes you can get for the same price, I can see why people might be reluctant about this anime (especially considering the ratings were terrible on Cartoon Network), but if you give this show a chance, you might find a full 500 episode (and counting) saga to delve into.