MFDC12 said:
witchblade has a great story too
Witchblade needs maybe that you know the comics first. As there's nothing explained, without begining or ending
Though, Madcow worked on the anime, so it's kind of an official story
Saikano was good
Claymore (but unfinished story ;_; )
Sports anime :
Do you like sports anime ?
Major (if you want to feel like you need the next episode right after the end of the current one, it's a good choice
)
Hikaru no Go
Old japan era :
Seirei no Moribito (good story, but I felt like it was unfinished)
Mecha & futuristic :
Gunbuster/Diebuster (Mecha in space)(a little old maybe, but a nice concept and idea)
Heroic Age (mecha in space)
Eve no Jikan (near futur only, no mecha but androids. watch the movie, it's a full recap of the series)
Freedom (Design by Katsuhiro Otomo)
Shoujo :
Fuujin Monogatari (nice graphical concept/idea)
Rec (very short story, interesting idea)
Funny or extreme lacking of common sense :
Jungle wa Itsumo, Hare nochi Guu
Arakawa under the bridge
Other :
Mushishi
Old gen anime :
Mysterious cities of gold (but USA had a different translation/story/music than French) (French producer will release MCoG 2 in 2011)
Nadia (Fushigi no umi no nadia)
Single Movie :
Toki wo kakeru Shoujo (modern day. a girl who acquires the power to go back in time).
Brave story (Heroic Fantasy)
Miyori no Mori (Princess Mononoke like)
Sorry, I made a lot of them, I don't know what genre you are searching for, so I separated them.