Tears of Kali is very good.

also mentionable: there are several german movies about real-life-cannibals, e.g. "die zrtlichkeit der wlfe" by ulli lommel, "der totmacher" by romuald karmaker or "cannibal" by marian dora (especially that one being quite disturbing and gory).
not to forget german vampire movies "nosferatu - phantom der nacht" by werner herzog (with a brilliant klaus kinski as dracula/nosferatu) and hans w. geissendrfers "jonathan".
maybe roland emmerichs early "joey" also belongs here.
and last not least the trash classic "hexen bis aufs blut geqult" aka "mark of the devil" by adrian hoven / michael armstrong!

Sorry to disappoint you but there are no German horror movies after the early black and white movies that are worth mentioning.
Germans are more into "Thriller" and "Romance / Comedy".
There are some productions though which are mainly german-made but with the usual Hollywood cast (i. e. Resident Evil).

Germany has never been a rich field in Horror (neither German film commissions as well as producers did like the genre too much, e.g. trusted it) but there are a few more remarkable Horror films that should be mentioned here, most of them are more cheesy, trashier ones but mostly quite enjoyable:
Magdalena - Vom Teufel besessen / Magdalena, Possessed by the Devil (1974)
http://german.imdb.com/board/10071795/
A sleazy Rip-off of "The Exorcist", mixed with the popular German Sexploitation Series "Schoolgirls Report".
Die Nackte und der Satan / The screaming Head (1959)
http://german.imdb.com/board/10053095/
Charming B-Movie with Frankenstein/Dr. Jekyll & Mr. Hyde-Elements, stylish and well made but a bit similar to the early Roger Corman Films.
Ein Toter hing im Netz / Horrors of Spider Island (1960)
http://german.imdb.com/board/10054333/
An extremely amusing B-Movie about a group of Dance girls who are confronted with monstrous spider creatures on a remote exotic Island after a plane crash. A must see, at least in the original German version.
Der Fluch der grnen Augen / The Curse of the green eyes (1964)
http://german.imdb.com/board/10058106/
Obscure and weird Vampire Movie by Hungarian director kos Rthonyi who also made the recommandable Edgar Wallace Film "The Devil's Daffodil" in 1961.
Die Schlangengrube und das Pendel / The Snake Pit and the Pendulum (1967)
http://german.imdb.com/board/10062235/
A campy adaption of Edgar Allan Poe's classic tale, very atmospheric and mysterious, yet sometimes unintentional funny because of some "shock"- and special effects. Overall, quite recommendable (it is available on DVD in Germany - the fine Disc also contains the english dub).
Parapsycho - Spektrum der Angst (1975)
http://german.imdb.com/board/10073514/
Probably never released in the USA, this obscure and strange flick is a hidden gem even in Germany itself. According to popular film critic Christian Kessler, it's worth to be seen.
Nachtschatten / Nightshade (1972)
http://german.imdb.com/board/10067473/
Obviously the only German "Arthouse"-Horror film, a slow, quite but creepy and dark Drama about a man who travels to a small village in the countryside where he is caught by visions of his own, mysterious death. Very rare but sometimes, it can be catched at German Television.
Flashback - Mrderische Ferien (2000)
http://german.imdb.com/board/10239406/
A German version of the new Hollywood Slasher films like "Scream", nice but only for fans of the subgenre.
Seven days to Live (2000)
http://german.imdb.com/board/10221928/
Shot in english with an international cast, this seems to be one of the better professional German Horror films.
Antikrper / Antibodies (2005)
http://german.imdb.com/board/10337573/
High Budget Mystery/Serial Killer-Thriller, said to be in the manner of "The Silence of the Lambs".
I wouldn't recommend the films of Olaf Ittenbach, Andreas Schnaas and Timo Rose - they mostly are only about gore and made on a semi-professional, amateurish base.

This message has been deleted.

The ending when the guy after getting electrocuted comes up again was cliched and I was very surprised to see that in a Euro Horror film, but yes it's great, also watch Das Experiment.
" It is in dying, that we awake to eternal life "- John Rambo

Thank you everyone; your recommendations are greatly appreciated.
"Pull the string, pull the string!" -Bela Lugosi

Well, there aren't really many good horror movies from Germany. Anatomie really is one of the better ones. Another good one is "Tattoo" (Link: http://www.imdb.com/board/10286204/).
"Sieben Monde" is okay. (Link: http://www.imdb.com/board/10130892/ )
"Funny Games" (Link: http://www.imdb.com/board/10119167/ ) is a really good one from Austria - but it's about sadistic killers entering the house of a family - so it's not a classic horror movie, more like a mix of "Panic Room" and "Clockwork Orange".
The "Edgar Wallace" Movies from the 60's partially also have pretty good horror elements and style. Actually Quentin Tarantino loves them. Anyway, most of them aren't really creepy anymore and today they better work as comedy (although some still have a creepy atmosphere).

Daniel?! Wargh! I'm into horror, but I'm not a pervert! (New tagline: He will howl you to deaf giggle before he will smash your wincing body under a cucumber-lorry")
Strange, I've posted in this thread an hour ago, but it is gone (not deleted, just gone! Weeeiiird!)
To recommend some german movies:

• Try "Das Experiment" (2001) a very good (imho) and disturbing movie about the abyss of society and the horror created by John Q. Public.
  Info: http://www.imdb.com/board/10250258/
• "Es geschah am hellichten Tag" (1958) this is an older black and white movie with Germany's darling Heinz Rhmann. I think there is an american remake with Jack Nicholson, the title is "The Promise". But I love the Original so much that I never could bring myself to watching the remake.
  Info: http://www.imdb.com/board/10051588/
• "Das Kalte Herz" (1950) This is a fairy tale brought to film. I loved this movie when I was young and I still enjoy watching it from time to time, even if it can't scare any more
  Info: http://www.imdb.com/board/10042627/
• If you like comedy, go looking for films by Loriot, who is (or rather "was" - he has quit the business, he thinks his humour is out of timeit's a shame!) a really good german comedian.
  Infos: http://www.imdb.com/board/10102629/
  and http://www.imdb.com/board/10094407/
• A good german drama is "Christiane F - Wir Kinder vom Bahnhof Zoo" (1981) This movie shows the drug caused decay of a young girl. In fact it's an autobiography brought to film and that makes it disturbing.
  Info: http://www.imdb.com/board/10082176/
  I can't think of more now, but if some more films should come to my mind, I will post them!
  PS: Sorry for the unclickable links, I don't know how to make them more comfortable!

The most horrifieing movie ever made in Germany must be "Daniel - Der Zauberer"
lol!!!! I did't see it but every german knows what you mean.

The most horrifieing movie ever made in Germany must be "Daniel - Der Zauberer"
This is not only horror, it is pure TERROR!
When you see this movie till the end, you sure will die.

I know also the movies of Olaf Ittenbach, very cruel Splatter and Gore Trash, jsut mention "Premutos - Der gefallene Engel", "The Burning Moon" and "Black Past", there all pretty Amateur-Like, and the Actors are,well, pretty laypersons.But afterwards there were bigger productions, like "Garden of Love", "Legion of the Dead" or "Beyond the Limits". Just check them out, i guess if youre living in the USA or other Countrys in Europe except the Uk theyre pretty easy to get!

I am not extremely familiar with German horror/exploitation flicks, as I've only seen a few of them, but Jorg Buttgereit's films are probably a good start. Nekromantik and its sequel were the first two movies of his that I watched, and they were actually surprisingly good (the first one moreso), albeit quite disturbing. Schramm is another decent title of his, and one that I've been meaning to watch again for quite some time now.
Jorg seems to go more for shock value than anything else though, and he definitely achieves that. The "climax" (bad pun to those who have seen it, I know) in Nekromantik is something that will stick in your head for years; very screwed up.
P.S. I almost forgot about "The Death King" from Jorg. Very warped and surreal; a good watch.