I really enjoyed Sakura Trick and there was another one i really liked but i cant remember the name~ i will post it if i remember ^.^
I haven't watched that many shows with indisputably canon yuri in it, but my favorite of those I have seen is probably Sasameki Koto.
I'm loving Strawberry Panic, although I haven't finished it yet. Kashimashi was probably my fav yuri so far... A bit on the short side though, sadly.